''Impossible Creatures'' is an 2003 {{RTS}} by Relic Entertainment (of ''VideoGame/{{Homeworld}}'' fame), where you take 2 of 76 creatures, combine their features and then use 9 of them in your army. Although the game was rather well received by critics, Impossible Creatures sold poorly, thus denying options of a sequel.

The campaign mode followed the story of IntrepidReporter Rex Chance, who teams up with scientist Lucy Willing in a quest to find his father, Dr. Eric Chanikov. He finds out about his father's death, and thus resolves to stop megalomaniac executive Upton Julius, who plans on using Sigma technology (combining animals) to rule the world.

The game's engine would later be reworked and used in ''VideoGame/DawnOfWar''.
!!''Impossible Creatures'' provides examples of the following tropes:

* ArtisticLicenseBiology: Porcupines don't shoot their quills in reality, but we wouldn't have one of the few range attacks in the game if it followed reality.
* AwesomeMcCoolName: "Rex Chance".
* CardCarryingVillain: Every single one of the villains; the BigBad [[TakeOverTheWorld wants to conquer the world]], his [[TheDragon "dragons"]] are a whaler, a FemmeFatale and a MadDoctor, and are all proud of it.
* CruellaToAnimals: Velika La Pette.
* DieselPunk: Set a vague amount of time after the Spanish Civil War, with technology far more advanced than anything in the 30's or 40's. Despite everything being coal-powered, it follows the DieselPunk aesthetic more as far as setting and building design.
* DesignItYourselfEquipment: or should we say design it yourself units.
* EverythingFades
* FakeLongevity: As ''Computer Games Magazine'' pointed out, there were countless combinations that one could make, yet only a handful of them were worth using.
* ForScience: Lucy Willing has this as one of her quotes, and it also characterizes her view of the Sigma technology [[spoiler: until they discover that the villains are experimenting with using it on humans.]]
* GlowingEyesOfDoom / ProphetEyes: For some reason all the creatures have white, glowing eyes. [[spoiler:After he is revealed to be a genetic experiment; Rex Chance's eyes become like those of the other creatures.]]
** In a limitation of the engine, even the normal animals you harvest DNA from have no pupils in their eyes.
* HeelFaceRevolvingDoor: Dr Ganglion [[spoiler: defects to Rex after his base is destroyed, then goes back to Upton in the final level.]]
* {{Homage}}: Lucy is captured by a giant gorilla called [[KingKong The King.]]
* HeyItsThatVoice / TalkingToHimself: Creator/LeeTockar‎ is Rex Chance, Whitey Hooten and Dr. Ganglion. DavidKaye is Upton Julius and the Henchmen. Creator/KathleenBarr is Lucy Willing and Velika Le Pette and Creator/SamuelVincent is every Villager.
* InexplicablyIdenticalIndividuals: All the henchmen look and sound alike, even in the cutscenes. The villagers too, even the African natives look the same as the Eskimos, except for clothing.
* InformedSpecies: The game has a "spitting cobra" that is bright ''blue.''
* LegoGenetics: The entire basis for the gameplay.
* MadScientist: Dr Ganglion.
* MixAndMatchCritters: Possibly the ultimate example. The game revolves around creating these and using them to fight other MixAndMatchCritters.
* MookFaceTurn: the source of your RedshirtArmy
* {{Portmanteau}}: The combined creatures' base names
--> '''Dr Ganglion''': Combine a Komodo Dragon with a Skunk, and you get a *snort*Komodo Drunk! Heh! Heheh! Quite funny!
* SeldomSeenSpecies: This game has poison dart frogs, archerfish, and muskoxen, among others.
* SpikeShooter: Porcupine DNA can grant this ability.
* TheTunguskaEvent: Leads to the story events