|Lost at Sea: Disappearance of the Mystery Disc|
|Season 3, Episode 8|
|Japanese Title|| 最後の戦い|
|Episode 55: Disappearing Hare Line||Episode 57: Furred Suezo's M-1 Grand Prix Hero|
Lost at Sea: Disappearance of the Mystery Disc is the eighth episode of Season 3 and the fifty-sixth overall episode of the Monster Rancher anime series. It aired in Japan on May 27, 2001.
Fed up with their failures, General Durahan sends out his Jelly Gaboos to deal with the gang. The baddies catch up with the group as they find themselves stranded on an abandoned ocean rig.
Mew Mum reports she has located Genki and his gang off the shore. Durahan calls out an army of Jelly Gaboo.
Holly tries to contact her father in the mystery disk. She recieves no reply. As the gang moves on Suezo spots an abandoned dock with a fishing rig. Tiger spots something in the water. He sends his lightning at the target revealing the Jelly Gaboo. Both sides engage in battle. As they battle a cannonball is shot towards them and knocks everyone off balance, causing the Mystery Disk to fly out of Holly's grasp and rolls into the sea. As Genki, Mocchi, and the Gaboos dive to retrieve the disk a submarine forces Genki and Mocchi to retreat. Out of the submarine pops out Gordish in a fit of rage accusing the young kids of taking his treasure. The gang asks for Gordish's help retrieving the disk and in return they offer to do chores.
The next morning Gordish, Holly, Mocchi, and Genki set off into the submarine. Holly guides Gordish to the Disk in a cave along with the discovery of a lost pirate ship. Unknwling the Jelly Gaboos follow them. A battle for disk and the treasure begins. Mocchi ends the game with Mocchi Cannon.
The treasure was lost but the disk was recovered.