Plot: While on his way to buy groceries, Peter instead buys a brain-damaged horse, which not only creeps everyone out but also causes $100,000 worth of damage when Peter enters it in a race and it goes on a rampage. Though the horse ends up dying of a fatal heart attack and Peter disposes of the body by flinging it into Mort Goldman's pharmacy, the Griffins are in debt for initial damages. To make money, Peter works as a test subject for medical experiments, being injected with various genes to see their effects; these include the squirrel gene, the Seth Rogen gene, and the gay gene amongst others.