If you eat it, in any period of time you can muster, you get a t-shirt. Trust me, the t-shirt is NOT worth the effort of eating this behemoth.
By the way, in the picture, her arm is nearly touching the back of the burrito - it isn't a trick of perspective. The thing weighs (supposedly) more than 6 pounds.
The only good things are that it is very tasty (for the first 70 bites or so) and it is cheap - only around $15 if I recall correctly.
I will not be doing this ever again.