Because of his co-star, Ben Stiller had to get a rabies shot.
Along with Ben Stiller and Jenifer Aniston, the movie’s titular ferret became a pop culture icon thanks to Along Came Polly. Both performers said in interviews advertising the film that they dislike ferrets. When Stiller’s character chases after Polly while clutching the ferret, the animal turns on him and bites his chin, but he refuses to let go. Stiller got rabies and now he won’t even let anybody else near his ferret because of it.