A brief setup: Eddies in the space-time continuum propel Peter out the Drunken Clam and into Moe’s, just as he is about to get into yet another epic monomachy with the Giant Chicken. This time Peter was determined to get in the first shot, but the punch he was aiming at his arch-nemesis lands on Lenny, knocking him onto a broken stool and killing him . Carl, naturally, immediately dies of grief; Moe, seeing half of his clientele perish, dies of shock; and Barney is already passed out on the pool table. Sick with rage, Homer immediately charges at Peter.
Given the intelligence level of both competitors and Peter’s long-standing rivalry with the Giant Chicken, it is probably likely that Peter would have no idea that he was in another place, especially seeing as Homer has skin of a yellow color similar to that of the Giant Chicken’s. This combination of rage and ignorance leads me to believe that Peter would continue to believe he was fighting the Giant Chicken and thus continue to fight with the rage and power that his usual skirmishes with the mascot involve. As Homer is about as intelligent as Peter is and can also fight back if provoked, such a battle would most likely result in the serious injury and/or death of both combatants.
If Stewie were to be transported along with Peter, or if Bart were to for some reason walk in and realize his father was in danger, the battle would most likely occur in a different fashion with victory given to the side with the extra member- but the involvement of both Bart and Stewie would also lead to a draw, given the equal number of combatants on both sides. Whether or not one or both of the combatants were intoxicated, as they often are, may also give one or the other drunken strength, but the outcome would still be the same. As Peter himself might put it, this reminds me of that time I accidentially hacked into NORAD and found out the only winning move is not to play.
Homer’s ability to withstand pain is astonishing, so, while it might appear that he is losing, he is actually just wearing down Peter in a prolonged rope-a-dope until Barney sobers up enough to hit Peter over the head with the pool cue lying next to him.
I really think Homer would be more inclined to notice that the beer taps were unattended than that his cronies were croaked. So he’d be on his back behind the bar, with his mouth directly beneath a stream of Duff.
And once nobody is hassling Peter, he’d belly up and ask for a Pawtucket Patriot. But I’m pretty sure he’d settle for a Duff.