->''"''[[AltumVidetur Natura non confundenda est.]]'' Loosely translated: don't fuck with Mother Nature."''
-->-- '''Dr. Thompson''' on the fate of the crew of Leviathan.

An underwater mining crew about to return to surface discovers a Russian sunken ship, Leviathan. However, said ship is supposed to be currently operating in the Baltic Sea and suspicion arises. The captain left a video log saying that the entire crew has fallen to an unknown disease, but the log cuts short as someone enters the captains's quarters. A crewmember referred to as Sixpack keeps a bottle of liquor found in the ship but it makes him sick the next day, and everything goes horribly wrong.

''Leviathan'' [[strike:is clearly inspired by]] stole everything from ''Franchise/{{Alien}}'' and ''Film/TheThing1982'' and never tries to hide it. This is not screenwriter DavidPeoples' best work. Special effects were done by Creator/StanWinston, and the music was composed by JerryGoldsmith, which only seems appropriate all things considered.

Leviathan was released in 1989, [[DuelingMovies the same year]] as ''Film/TheAbyss,'' and was promptly forgotten. B-movies starring Creator/PeterWeller and Amanda Pays seem to have this as a recurring theme.

Not to be confused with the movie of the same name made by Andrey Zvyagintsev.

* ApocalypticLog: The video tapes the crew finds on the sunken Russian vessel turn into this as they watch them. The last entry is of a very nervous commanding officer saying something has gone wrong...and the door to his quarters slowly opening behind him...
* ArtisticLicenseBiology
** Apparently trying to give people gills will turn them into something out of ''Film/TheThing1982'', complete with the ability to infect and absorb any lifeform they come in contact with. Does anyone else think this is a roundabout way to get gills?
** After discovering the fused bodies of two infected crewmembers, [[Film/TheThing1982 totally original by the way]], they decide to flush them out the air lock. They flush the monster with gills out of the air lock into the ocean, [[CaptainObvious which is full of water]], I just, what were they, ARRGH!
*** Probably something along the lines of "HOLY FUCK WHAT THE FUCK HAPPENED GET RID OF IT GET RID OF IT NOW." and that's where they stopped. Would YOU care about the finer details if you found some mutated abomination horror that seemed to be dead?
* BioAugmentation / TestedOnHumans: This is what was attempted with the Leviathan crew. It ''did'' work but definitely not in the way that it was supposed to.
* BlackDudeDiesFirst: An extreme and cruel [[spoiler:inversion. The very last death, about 100 seconds before the credits roll, after the survivors reach the surface and ''are already being rescued by a helicopter crew'' is Jones.]]
* BodyHorror: The mutation takes over the host body and makes it a creepy, eel-like mess of tentacles and teeth.
* BodyOfBodies: The dead/infected crewmembers eventually join together to form a mess that doesn't really look like anything.
* ChainsawGood: The cast arm themselves with saw-like mining tools when the monster attacks grow in intensity.
* CorruptCorporateExecutive: Martin.
* DevelopingDoomedCharacters: For forty minutes.
* DrivenToSuicide: Bowman after seeing Sixpack's corpse and realizing what was happening to her.
* DullSurprise: Damn it Beck, if the base is falling apart and monsters are stalking through it, it means you should EMOTE SOME, PERHAPS!
* EverythingsEvenWorseWithSharks: When the crew finally manages to get to the surface, they are briefly attacked by sharks.
* FanDisservice: We get Bowman in nothing but a towel but she's infected with an illness that has scales growing on her neck and her hair falling out. Then later on we get her naked [[spoiler: in the shower after she's slit her wrists]].
* {{Fanservice}}: The movie manages to find an excuse to get Amanda Pays down to her underwear.
* FateWorseThanDeath: The crew members who get infected throughout the movie are shown to retain their consciousness far into the physical transformation, even past merging with each other.
* GoneHorriblyWrong: What happened with the titular ship Leviathan and subsequently to the mining station. It's almost a textbook example.
* ImColdSoCold: Cobb right before the inevitable.
* LegoGenetics
* PreMortemOneLiner: Peter Weller gets the best one before [[spoiler: putting a grenade in Leviathan's mouth blowing it up.]]
--> '''Steven Beck:''' SAY AHHH!!!! MOTHERFUCKER!!!!!
* RecycledInSPACE: Leviathan is basically ''The Thing'' set in an underwater mining base, with elements of ''Alien'' as well (particularly the titular ship, ''Leviathan'').
* ShowerOfAngst
* SovietSuperscience
* TheVirus: The unintended result of the Leviathan experiement.
* ThrownOutTheAirlock: The underwater version of this is attempted twice in the film and it still backfires both times.
* TooDumbToLive: Sixpack and Bowman drink liquor found on a sunken ship where the crew had mysteriously died from a contagious illness.
* UnderwaterBase: The mining station.
* WhatCouldPossiblyGoWrong: Secretly feeding a ship crew chemicals that will cause mutations doesn't sound like a good idea in any context.
* ZombieInfectee: Cobb is a strange subversion. He's clearly infected and everyone is much aware of this but he keeps fighting the monster with the other remaining survivors until his transformation finally kicks in with full force.