During the Credits
There are no extras during the credits of The Sorcerer’s Apprentice.
After the Credits (spoilers)
After the credits of The Sorcerer’s Apprentice there is a scene showing a real life version of Mickey’s hat from the animated Sorcerer’s Apprentice in a library with other old items. As the camera moves away from Mickey’s hat, it pans to Horvath’s hat and someone (presumably Horvath) picking it up and leaving behind a roach.