Some people think Mabel has a secret doppelganger named Lebam. Evidence for this theory comes from The Deep End, in which Mermando's last two bottles seem to be addressed to "Lebam".
More evidence comes from Boyz Crazy. When Mabel, Candy and Grenda discover that Bratzman has been arrested, Candy and Grenda run away to tell the boys, leaving Mabel downstairs. But Mabel arrives upstairs in front of the door ahead of her friends. We're led to believe she just has cartoon-character speed, but some would say that the Mabel that stopped Candy and Grenda and went mad with power was Lebam.
In Land Before Swine, we see pictures from Mabel's Pig Dance Party. Some theorists stretch this to mean that someone (namely Lebam) was taking the pictures. I think that's ridiculous.
Possibly the best "evidence" for Lebam's existence comes from MGT Dating. In one shot, Mabel is seen holding up "Zach" and wearing a purple sweater. In the interview before and after, she is wearing a blue sweater. However, she could've just filmed these two shots at different times and/or dates.
Personally, I think this is a bit far-fetched. The idea of Mabel hiding something from us, especially something that big, is just plain creepy.
