Term used on the Internet to indicate confusion about, and often to point out a contradiction within, something someone else has said.
Person A: I like unicorns. Their scales are lovely.
Person B: Unicorn scales? Wait, what?
What you say when one (or more) of your friends is talking to you, and you are daydreaming about something completely unrelated. Usually said after saying something else, completely random.
You: I like Tacos. Wait, what?
Said often after coming to the realization that what someone has just said is either offensive to you, or someone you care about.
Dude 1: Saw you mom last night.
Dude 2: Oh, really? Where at?
Dude 1: On cops, they busted her for prostitution.
Dude 2: Oh, that's nice. Wait, what?
1. Term used after saying something rather perverted or offensive. Said to make it look like whoever said it, was actually joking but a majority of the time they are not.
2. Used to deflect personal responsibility from a blunt comment.
1. Me- "Hey, how's your day going? Oh yeah, I want to do you in the ass! Wait, what?!"
Girl- "Uh, excuse me?"
Me- "I don't know what you're talking about..."
2. Me- "Why don't you quit being such an asshole? Wait, what?"
You- "What the hell did I do?"
Me- "Um, I was just joking?"