Simulacra

Simulacra are humanoid xenos eith slender, pink, fleshy bodies, bulbous forearms and lower legs, and a pointed, featureless head. Simulacra can take on the form of a being for a limited time after consuming that creature's brain, this effect allows them to behave as that individual for the duration of their transformation, knowing everything their prey knew. They're essentially doppelgangers.