An amulet Kiki's father made from a lion shark tooth tooth ten years ago, when he decided to become a fisherman.
The Shark Tooth Amulet is made by Kiki's father in Arni, Home World and originates from a giant Lion Shark. He made it in 1010 A.D., the year he decided to become a fisherman. It is given to Serge, who showed it to Kiki's father in Another World. Though the alternate Kiki's father denied the existence of a fisherman counterpart and noted that he had no regrets about his decision to become an occultist, the scene did wake up Mojo, who accompanied Serge from that point on.
From: Key Items (Chrono Cross)