Do you hear that snickering sound? Sounds so... mischievous. For fans of the old Wacky Races, this super bright, Wacky Races Muttley Heat-Sensitive Morphing Mug features Muttley the dog and his most famous quote, "Heheheheh." The exterior of this 11 oz. mug transforms from black as hot liquid is added, revealing the hidden image in full vivid colors. Makes a great gift for fans of the Hanna-Barbera series Wacky Races. Hand wash only. Not dishwasher safe. Do not microwave.