A puppy

Erin couldn't understand why Rock had agreed to keep Tommy Smith, a local radio personality, as a house pet.
"He isn't housebroken?" she said. "What were you thinking?"
"I know it seems crazy, but it's not as bad as all that," Rock said. "He just doesn't like to be outside. I mean, he's not going to go on the floors or anything."
Later, just as dawn began to break, Tommy was a puppy—a boxer who seemed eager to dash out of the front door with Jo the cat.