Robin - for the dog who follows your other dog who is named Batman around. (male)
Poison Ivy - Have a dog that loves plants? (female)
Harley Quinn - for the dog with the high-pitched, annoying voice. (female)
The Joker - great for a dog who laughs almost all of the time, and has blue fur. (male)
The Riddler - for the dog who can never give you a straight answer. (male)
Mr. Freeze - have dog that is always sticking it's cold nose on you? (male)
Clayface - for the dog that looks different everytime you see him. (male)
Cat Woman - a female dog who is more cat than dog. (female)