Possession (Chapter 1, Song 3)
Despite Lois' protests, her, Chris, & Meg escape the house. Stewie yells at them for leaving him behind, and prepares for a fight he might never forget...

As Stewie was packing his bag, the door has been broken down by Brian... or that's what Stewie thought, until he grabbed Rupert, and ripped him to shreds, infuriating the poor little child. Stewie then assaults Brian, still pissed that Brian was too stubborn to pay him over a bet.

AHRIMAN, watching the scene was pissed that things were not going his way, and made the move of possessing Brian, mutating him while doing so. Stewie was surrounded by Brian, Rupert, & AHRIMAN, getting semi-corrupted due to Brian jabbing at him. He jumps out of the window, but his corrupted eye gets stabbed by a glass shard. THE HUNT HAS BEGUN....