That's because the carbon dioxide in the beer forms bubbles that fluff up the batter, and foaming agents, which are certain proteins found in beer, keep those bubbles from bursting as fast as they normally would.
We didn't really think about the rheology of jelly and banana being so soft and kind of mushy that it kind of just crumbled as soon as the graham cracker paste kind of created a ceiling on top of it.
Depending on whim and availability, guests to Buckland's house might be served baked guinea pig, mice in batter, roasted hedgehog, or boiled Southeast Asian sea slug.