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A super-size shake in a super-size cup at mcdonalds with all of the flavors in it.
Dude, i can't belive you drank another Mcshitty!
by trots December 11, 2008
A meal ordered through the McDonalds drive through that turns out to be the wrong order, but you have already started to drive away. You are pissed if you have to turn around and return it, but just as pissed you didnt get what you paid for.

can be reffered to as a

Biggiesized McShitty- When its your 3 yo kids who get the McShitty insted of their McHappysack, and you have already started to drive away.
Driver: hey dude, can you pass me the double cheeseburger i ordered, im fuckin hungry.
Passenger: Damn it, they gave you a McShitty instead.

3yo kid: whhaaahaaaaaaahaaa!!!!!!! I WANT MY GOD DAMN HAPPY MEAL!!!! Whahwahhhhahhaaaaaa!!!!!

Driver: For christs sake, did they have to Biggiesize that McShitty.
by CHOUL aka Patches O'Houlihan August 23, 2007