Result of switching the "t" and the "b" in the phrase "Big n' tasty." A term of frustration used when you go to McDonald's or an equivalent fast food restaurant, order something, and the cashier or person behind the drive-thru window attempts to repeat what you said in either unintelligible language or something totally contrary to what you asked for. This is a stupid, yet somewhat gratifying, way to respond.
Employee behind drive-thru window (speaking in bad microphone): Welcome to McDonald's. May I help you?
Me: Yes. I would like a large #2, diet coke, and some cookies.
Me: Yeah fool. I want a tiggenbasty!