Pete's formula was a potion concocted by Pete Clarner, a Sunnydale High student, in order to increase his strength and virility, though it also mutated him into a clawed monster. Initially, Pete had to drink the formula to transform, but eventually its effects became triggered by anger. In this state, Pete was powerful enough to face off against Buffy, a transforming Oz and a feral Angel and do fairly well, although he was hampered by his inability to think beyond his rage.