Bud and Lou

Bud and Lou are a pair of spotted hyenas that appear in DC Comics. Their names are references to the comedy duo Abbott and Costello.
Fictional biography.
Bud and Lou are spotted hyenas who are the pets of Harley Quinn. When Harley Quinn wanted to go solo and formed her gang, their first mission was to free Bud and Lou from the Gotham City Zoo.
At some point, white collar criminals stole Bud and Lou from Harley Quinn so that they can auction them off as exotic pets. Upon locating the place of the auction, Harley Quinn reclaimed her hyenas and had Poison Ivy wreck the place.
In September 2011, The New 52 rebooted DC's continuity. In this new timeline, Bud and Lou are still featured as Harley Quinn's pets. In the "Death of the Family" storyline in an attempt to drive Harley mad, Joker gives them rabies and sics them on her, forcing Harley to (apparently) kill them in self-defense. In Harley Quinn’s solo series it is revealed that Bud and Lou survived the ordeal and recovered at a zoo, where they sired puppies with several of the zoo’s female dogs. 
Powers and abilities.
Bud and Lou mostly attack with their claws and fangs.