One would assume Peter Griffin and Homer Simpson, the patriarchs of Family Guy and The Simpsons, could easily be best buddies. However, a debate over beer has the two FOX characters trading blows in a five-minute preview that aired at Comic-Con.

The two FOX stars and their families appear to hit it off at first, sharing donuts and prank calls (which leads to Stewie making an unfortunate rape joke). Peter also manages to include Homer in one of Family Guy's infamous cutaway gags, where the two are World War I aces and have to "carry" Bob from Bob's Burgers.

However, things sour when Homer tries Peter's Pawtucket Patriot beer, which Homer claims if a rip-off. After some meta jokes about Family Guy's similarities to The Simpsons, the two men end up fighting in an extended scene not unlike Peter's battles with the Giant Chicken.

The crossover will air on FOX September 28, the same date as the highly-anticipated season premiere of The Simpsons during which a major character from the series will die.