A bear that appeared in "Grubble Gum" and "The Birthday Suits", he is very bad tempered and attacks anyone who wakes him up. Mung asks if he could get him Chowder, and Schnitzel unstuck from the gum but he got stuck too. Then he tries to use steam but just made it worst.

NOTE: Mr. Grumpy is not to be confused with the Mr. Grumpy from Mr Men.