The Whisker From Cerberus is one of the Five Sacred Items you must get in Mythology Island.
How To Get It[]
To obtain this item you must first go to Apollo's temple and get a reed pipe. Then talk to the muse with the pipe and she will challenge you to a memory game. Beat this game and she will give you a magic tune. Go to the underworld and play the tune on your reed pipe in front of Cerberus. He will fall asleep and you can take the whisker.
Secret Message[]
The Secret Message it comes with is "objects will rule".