The occurrence when, unknowingly, you eat a beignet, and then later, after stating you have not eaten a beignet, you are told you have, in fact, eaten a beignet.
Person #1: You know, I've never eaten a beignet.
Person #2: Yes, you have. I made you some for Christmas.
Person #1: Oh, really?
Person #3: BEIGNETCEPTION!