(Part 1 is here.)

You all remember the chestburster from the first Alien movie, right?

http://www.sandiegoreader.com/users/photos/2013/sep/30/53953/

That nasty little fellow poked his head out in 1979. Two years later, James Cameron gave us this in Piranha Part 2:

http://www.sandiegoreader.com/users/photos/2013/sep/30/53954/

I'm not saying he was ripping off Alien. I'm saying he was serving notice that the seeds of Aliens, the sequel he would write and direct, were being sown in Piranha Part Two, the sequel he was currently writing and directing. There are just so many similarities.

Consider: our heroine leads a dive down to the wreck that is home to the mutant piranha. One of her chargers disobeys orders and swims inside. He gets eaten. She sees his mauled body. Cut to interrogation from the local authorities:

http://www.sandiegoreader.com/users/photos/2013/sep/30/53955/

Police Chief: This incident took place on one of your regularly scheduled dives?

Anee: Yes.

Police Chief: Did you see what happened?

Anne: He just swam away from the rest of the group.

Police Chief: Did you see a shark at any time?

Anne didn't see a shark, but she knows it wasn't a shark. So Police Chief Steve asks, "What was it?"

Anne: l don't know. That's the point. l'm familiar with the marine life in this area, and l don't know! l've gotta look at the body. l only saw it for a moment.

Police Chief: Out of the question. That's the coroner's job.

Anne: Steven. l was responsible for that boy. That's my job. l have to know what happened.

Police Chief: That's right. You were responsible, and that's precisely why you can't touch the body. Because it may be used in evidence in a case of negligence.

Okay, so the heroine knows something bad is out there, but no one else knows, and the circumstances are such that it looks like the problem might be with her. Negligence! Eventually, Anne insists to her boss that the resort shut down its water activities until the danger can be dealt with. For her troubles, she is fired.

Fast forward to the opening of Aliens. Ripley, having survived her go-round with the xenomorph in Alien, is now facing a review panel after her escape pod gets picked up:

                               VAN LEUWEN
                Look at it from our perspective.
                You freely admit to detonating the
                engines of, and thereby destroying,
                an M-Class star-freighter.  A
                rather expensive piece of hardware...

                               INSURANCE INVESTIGATOR 
                       (dryly)
                Forty-two million in adjusted dollars.
                That's minus payload, of course.

                               VAN LEUWEN
                The shuttle's flight recorder
                corroborates some elements of
                your account.  That the Nostromo
                set down on LV-426, an unsurveyed
                planet, at that time.  That
                repairs were made.  That it resumed
                its course and was subsequently set
                for self-destruct.  By you.  For
                reasons unknown.

                               RIPLEY
                Look, I told you...

                               VAN LEUWEN
                It did not, however, contain any
                entries concerning the hostile
                life form you allegedly picked up.

    Ripley senses the noose tightening.

                               RIPLEY
                Then somebody's gotten to it...
                doctored the recorder.  Who had
                access to it?

    The ECA (Extrasolar Colonization Administration)
    Representative (ECA REP) just shakes his head.

                               ECA REP
                Would you just listen to yourself
                for one minute.

    Ripley glares at the ECA Rep, a woman on the ungenerous
    side of fifty.  Van Leuwen sighs with exasperation.

                               VAN LEUWEN
                The analysis team which went over
                your shuttle centimeter by
                centimeter found no physical
                evidence of the creature you
                describe...

                               RIPLEY
                       (losing it) 
                That's because I blew it out the
                Goddamn airlock!
                       (pause)
                Like I said.

                               INSURANCE MAN
                       (to ECA Rep)
                Are there any species like this
                'hostile organism' on LV-426?

                               ECA REP
                No.  It's a rock.  No indigenous
                life larger than a simple virus.

    Ripley grits her teeth in frustration.

                               RIPLEY
                I told you, it wasn't indigenous.
                There was an alien spacecraft there.
                A derelict ship.  We homed on its
                beacon...

                               ECA REP
                To be perfectly frank, we've surveyed
                over three hundred worlds and no one's
                ever reported a creature which, using
                your words...
                       (read from Ripley's
                       statement)
                ...'gestates in a living human host'
                and has 'concentrated molecular acid
                for blood.'

    Ripley glances at Burke, silent at the far end of the
    table.  His expression is grim.  Her mouth hardens as
    a bit of the old nail-eating Ripley surfaces.

                               RIPLEY
                Look, I can see where this is
                going.  But I'm telling you those
                things exist.  Back on that planetoid
                is an alien ship and on that ship
                are thousands of eggs.  Thousands.
                Do you understand?  I suggest you
                find it, using the flight recorder's
                data.  Find it and deal with it --
                before one of your survey teams
                comes back with a little surprise...

                               VAN LEUWEN
                Thank you, Officer Ripley.  That
                will be...

Okay, so the heroine knows something bad is out there, but no one else knows, and the circumstances are such that it looks like the problem might be with her. Negligence! She insists that they go back and wipe out the alien threat, and for her pains, she loses her job. The only job she can get is one running loaders.

Back to Piranha Part 2. Eventually, Anne gets a chance to do some investigating, aided by a seemingly friendly true believer Tyler. But it turns out he knew all along about the mutant fish - he just wasn't telling Anne! Here he is making a secret call back to his bosses.

http://www.sandiegoreader.com/users/photos/2013/sep/30/53956/

Gosh, is there anyone in Aliens who is a seemingly friendly true believer out to help the heroine? Who we later find out knew about the alien menace all along? Why yes, yes there is. His name is Carter Burke.

http://www.sandiegoreader.com/users/photos/2013/sep/30/53957/

Eventually, Anne finds out that Tyler knew about the mutant killer fish. She freaks out. She wants to go after them. He replies, "I've got to get more information so I can fill out my report! Then I can submit it to the proper authorities, who are qualified to handle this! The people on this island aren't qualified to handle this!"

Compare to this scene from Aliens, in which Burke, the film's Tyler character, balks at the notion of nuking the alien nest from space:

                             VASQUEZ
               All right, we can't blow the fuck
               out of them...why not roll some
               canisters of CN-20 down there.
               Nerve gas the whole nest?

                              HUDSON
               Look, man, let's just bug out and
               call it even, okay?

                              RIPLEY
                      (to Vasquez)
               No good.  How do we know it'll
               effect their biochemistry?  I say
               we take off and nuke the entire
               site from orbit.  It's the only
               way to be sure.

                              BURKE
               Now hold on a second.  I'm not
               authorizing that action.

                              RIPLEY
               Why not?

    Burke senses the challenge in her tone and backpedals
    flawlessly into conciliatory mode.

                              BURKE
               Well, I mean...I know this is an
               emotional moment, but let's not
               make snap judgments.  Let's move
               cautiously.  First, this physical
               installation had a substantial
               dollar value attached to it --

                              RIPLEY
               They can bill me.  I got a tab
               running.  What's second?

                              BURKE
               This is clearly an important
               species we're dealing with here.
               We can't just arbitrarily
               exterminate them --

                              RIPLEY
               Bullshit!

                              VASQUEZ
               Yeah, bullshit.  Watch us.

                              HUDSON
               Maybe you haven't been keeping up
               on current events, but we just got
               out asses kicked, pal!

    Ripley faces Burke squarely and she's not pleased.

                              RIPLEY
               Look, Burke.  We had an agreement.

    Burke moves in, lowering his voice.  He takes her aside
    from the others.

                              BURKE
               I know, I know, but we're dealing
               with changing scenarios here.  This
               thing is major, Ripley.  I mean
               really major.  You gotta go with
               its energy.  Since you are the
               representative of the company who
               discovered this species your
               percentage will naturally be
               some serious, serious money.

    Ripley stares at his like he's a particularly
    disagreeable fungus.

                              RIPLEY
               You son of a bitch.

                              BURKE
                      (hardening)
               Don't make me pull rank, Ripley.

                              RIPLEY
               What rank?  I believe Corporal Hicks
               has authority here.

                              BURKE
               Corporal Hicks!?

                              RIPLEY
               This operation is under military
               jurisdiction and Hicks is next in
               chain of command.  Right?

                              HICKS
               Looks that way.

    Burke starts to lose it and it's not a pretty sight.

                              BURKE
               Look, this is a multimillion
               dollar operation.  He can't make
               that kind of decision.  He's just
               a grunt!
                      (glances at Hicks)
               No offense.

                              HICKS
                      (coolly)
               None taken.
                      (into mike)
               Ferro, you copying?

                              FERRO
                      (voice over; static)
               Standing by.

                              HICKS
               Prep for dust-off.  We're gonna
               need an immediate evac.
                      (to Burke)
               I think we'll take off and nuke
               the site from orbit.  It's the
               only way to be sure.

    He winks.  Burke looks like a kid whose toy has been
    snatched.

                              BURKE
               This is absurd!  You don't have
               the authority to --

The same ideas are in play: "Yes, people are dying, but the grunts on the ground aren't qualified to handle this. We need to take this information to the higher ups."

Oh, and why are the mutant piranha where they are? Because, says Tyler, "four canisters of fertile piranha eggs sank right there." So the problem is being near to a nest of eggs nestled in the hull of a crashed ship, huh? You mean sort of like this?

http://www.sandiegoreader.com/users/photos/2013/sep/30/53958/

Moving on. Why doesn't Burke want to nuke the alien nest?

                            BURKE
               Those specimens are worth
               millions to the bio-weapons
               division.  Now, if you're smart
               we can both come out of this
               heroes.  Set up for life.

Right. Because the aliens would be awesome bio-weapons. Hey, I wonder where the mutant piranha came from in Piranha Part 2?

Tyler: Maybe it's a new kind of species, you know. Something that never existed before.

Anne: Like a mutant strain or genetic engineering?

Tyler: Yeah, l guess. Anybody doing stuff to fish?

Anne: The Army was, but that was several years ago. They developed a sort of killer fish to screw up the rivers in Vietnam.

Tyler: Apocalypse Two. And Three and Four.

Anne: They escaped from their tank and killed a lot of civilians.

Bio-weapons that kill civilians! Like all the colonists on LV-246!

I could go on, but let's just wind this up with a couple of notable scenes. Anne and Tyler dive down to the wreck that holds the piranha nest and plant some bombs to blow up the baddies. They try to escape the wreck through a narrow duct, but Tyler gets caught. He dies, but while the fish attack him, Anne is able to escape.

Aliens: Vazquez, Gorman, Ripley, Hicks, and Newt are crawling through ductwork, trying to escape the aliens:

    They try to crawl back, jamming together.  Behind them,
    the way they have come, a GRATING is battered in with a
    FEROCIOUS CLANG and the deadly silhouette of a warrior
    flows into the duct.  They are trapped.  Vasquez uses
    her flamethrower, bathing the tunnel in fire.  Hicks
    snaps out his hand-welder and cuts into the wall of the
    duct.  Molten metal spatters him, as sparks fill the
    tunnel with lurid light.  Vasquez' flamethrower sputters.

                              VASQUEZ
                      (icy)
               Losing fuel.

    Between eye-searing bursts of flame Ripley sees the
    glistening apparitions closing in.  Hicks' torch feathers
    out.  Empty.  Bracing his back he kicks hard at the
    cherry-hot metal.  It bends aside.

    Beyond is a narrow SERVICE WAY, lined with pipes and
    conduit.  Hicks slides through the searing hole,
    lifting Newt safely through as Ripley hands her out.
    Ripley follows and turns to help Gorman.  Vasquez'
    flamethrower goes dry.  She draws her SERVICE PISTOL.
    Suddenly she looks up as a WARRIOR SCREECHES DOWN FROM
    A VERTICAL SHAFT, right above her.

    She fires with incredible rapidity...BAM!  BAM!  BAM!
    Rolls aside.  It lands on her legs and she snaps her head
    to one side just as its TAIL STINGER buries into the
    metal wall beside her cheek.  She fires again, emptying
    the pistol, kicking the thrashing shape away.

    Acid cuts through her chickenplate armor, searing into
    her thigh.  She cries out, gritting her teeth against
    the white-hot pain.  Gorman sees Vasquez hit, unable to
    move.  Sees the creatures coming the other way...and
    turns away from the escape hole.  He crawls back to her,
    grabs her battle harness and starts dragging her towards
    safety.  Too late.  The approaching alien warriors have
    reached and passed the opening.  Vasquez sees him,
    barely conscious.

                              VASQUEZ
                      (hoarse whisper)
               You always were an asshole, Gorman.

    She seizes his hand in a deadly drip, but we RECOGNIZE
    it as the "power greeting" she shared with Drake...
    something for the chosen few.  Gorman returns the grip.
    He hands her two grenades and arms two himself as the
    creatures are upon them.

They die, but while the aliens attack them, Ripley and Newt are able to escape. Oh, and speaking of Newt, the little girl that Ripley feels compelled to save. There's this scene in Piranha Part 2 where the fish come flying out of the water and start eating everybody on the beach. There's a panic, and everyone's trying to get inside the hotel, but Anne pauses to rescue a little girl:

http://www.sandiegoreader.com/users/photos/2013/sep/30/53965/

And finally...the big bang at the finish. We all remember the friendly computerized voice in Aliens, advising Ripley that she now has one minute to reach minimum safe distance before the whole place blows up. Yeah, here's the bomb in Piranha Part 2:

http://www.sandiegoreader.com/users/photos/2013/sep/30/53966/

Anne planted it, just like Ripley started the meltdown. Now Anne has to swim far enough away not to get blown to pieces, just like Ripley has to fly far enough away not to get blown to pieces. And in both cases, who's flying the ship (or boat) that carries her to safety in the nick of time? LANCE FREAKING HENRIKSEN.

http://www.sandiegoreader.com/users/photos/2013/sep/30/53969/

Amazing.