Deathclaw (Fallout: New Vegas)

Deathclaws are an enormously large, agile, and strong species of mutant chameleons created through genetic engineering. They are substantially larger than a human, and have large and dangerous claws. However, due to mutation, they have lost their camouflage ability.

Background
The deathclaws were originally created before the Great War by the United States Military in order to replace humans during high-risk close-combat search-and-destroy missions. They were Jackson's Chameleons genetically modified with the DNA of various other species.