Cerberus

Cerberus is the name of a multi-headed dog in Greek mythology. A similar creature by the name of Fluffy also exists in Harry Potter And The Philosopher's Stone.

Empath: The Luckiest Smurf stories
Cerberii (the plural form of the name of the creature) are known to exist in the EMPATH: The Luckiest Smurf story series, and are listed in the Smurfs' Fantastic Beasts And Where To Find Them book.