Arthur: I know how to prove which one of us is the real Arthur. I'll tell you something only the two of us would know.
The Tick: Uh, okay.
Arthur: Tick, remember when my sister got me that V-neck sweater for my birthday and we tried to return to the store, but they only gave us store credit? And then at the diner, I ordered a cheeseburger, and it came with onions, even after I specifically told the waitress I didn't want any onions. Remember that day, Tick?
The Tick: Indeed I do! (to Arthur Clone) Okay, your turn.
Arthur Clone: I Arthur.
The Tick: Can't argue with that.