It is said there is an ancient artifact hidden inside the cave. However, no one has ever been able to get it before Goku's arrival on Grand Kai's planet. After completing the Battlefield Royale challenge, and beating Olibu in front of the cave, Olibu leads Goku inside the Cave of the Ancients. Goku blows a steel door open inside the cave with a Kamehameha, and then the two warriors arrive in front of a wall made of Katchin, the strongest metal in the universe. Goku uses his Instant Transmission technique to pass the wall, and gets the Cotton Gi from a chest.