Who Let the Dogs In? is an episode from Foster's Home for Imaginary Friends and is the 11th episode in season one. It aired on June 6, 2003.
Eduardo finds a puppy inside in the house and decides to keep it regardless of the rules of having no animals in the house.
The puppy begins to cause problems where Eduardo has to try and cover up for the puppy's problems.
Before long though, it is revealed that there are more than one puppy where Mr. Herrimen finds out, only to see that the puppies are all imaginary and that the group gets to keep them in the end.