Mars Inc., Delirious
An attractive surf bum comes in from an afternoon of waves. As he walks in, he's holding his stomach and his apparent girlfriend, a svelte blonde in workout clothes, says, "Hey, what's wrong baby?"
He lays down on the couch moaning, and says, "Sooo hungry." She reaches into a cabinet and hands him a candy bar. He unwraps it and after his first bite looks back at her -- except she suddenly appears to have a beard. With fuzzy vision, he apparently hallucinates as she appears to transform into a man, who asks if he's okay.
The surfer now stares in amazement and asks, "What the?" The other person is now fully a man looking back at him oddly, and says, "Are you alright, man?"
The years-long tagline follows, "Snickers Really Satisfies."
The message of this ad is as hazy as the man's vision -- is he hallucinating from hunger or from a bite of the Snickers bar? Was he really with his girlfriend in the first place or his mate? The humor of the commercial is in the "horror" of seeing his girlfriend as a man.
While few would wish their romantic partner as the opposite gender, the humor could also have worked for her to be another woman -- which may have brought a smile to his face if she was sexy too -- or his mother. However the humor is "heightened" here by making it another man, thus a somehwat homophobic laugh for viewers.