THE GUEST Alec Baldwin

THE CHARACTER Caleb Thorn (from ''Bonfire of the Manatees,'' 2007)

Enraged by Homer's ill-advised foray into adult-film production (''Lemony Lickit: A Series of Horny Events''), Marge storms off...and finds solace in the arms of Dr. Thorn, a marine biologist dedicated to the protection of manatees. Marge, of course, ends up back in Homer's doughy embrace, but not before she's subjected to lotsa hilarious sensitive-guy blather — which Baldwin delivers with much briny brio. —Wook Kim