A phrase originating from the video game Naruto: Clash of Ninja 2. The second half of the phrase originates from the phrase Believe it!. Originally used on the extras menu, it is used as an over enthusiastic response for something that one would not consider a "bonus" at all.
It is commonly used as punchline in a joke involving someone about to receive or do something somewhat desirable (engage in intercourse, win a prize on a game show, make a purchase). The second person mentions something very undesirable in addition to the initial object/act. The first person indicates their displeasure, while the second exclaims the phrase.
1: Congratulations! You've won a brand new car!
2: OMFG! This is the greatest day of my life!
1: But you'll have to time to use that car, as you've won a trip to maximum security prison!
2: WHAT?!
1: IT'S A BONUS! BELIEVE IT!
by Cube B August 26, 2007
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