Fringe: Season 1, Episode 16

1 - 16: Unleashed

When animal rights activists ransack a laboratory, they accidentally release a man-made chimera with a ferocious appetite. Walter suspects that his research helped to create it. The creature leaves a trail of grotesquely mutilated bodies in its wake, some of which it injects with its larvae. Charlie survives such an encounter with the creature, and the Fringe Division must race to capture it for a sample of its blood before the larvae eat their way out of Charlie. Olivia discovers the source of the creature, and that it was created based on work by one of Walter's peers, not Walter himself. Walter risks his life to capture the creature and succeeds, allowing them to save Charlie.