Wikipedia
Evolva is a third-person action game created by British computer artist William Latham, released in 2000. The player leads a team of 4 "GenoHunters" exploring a planet; each of the GenoHunters can develop new abilities by incorporating and altering the DNA they've absorbed from the creatures they have killed. The GenoHunters will change their physical appearance (change colors, develop spikes or horns) based on the DNA they've used to mutate themselves. Genohunters can punch, jump, super jump, breathe fire, vomit flammable liquids, shoot explosives, scramble enemies' brains, and spawn small alien offspring that injure enemies. Prior to the game's release, developer Interplay Entertainment repeatedly advertised that there are over 1 billion possible variations on the basic Genohunter.
The game has 12 large, linear levels populated with alien insect-like creatures known as the "parasite guardians". There are different types of these alien creatures. In some of the levels there are "Bosses" at the end which your team of genohunters must defeat.