The Sea of Protodermis was the floor of the Coliseum. It was made up of hundreds of moving pillars, which simulated an ocean. When the Toa Metru announced themselves, the false Turaga Dume put them through the Sea of Protodermis for a test, which they failed. Then later, during the battle between Sidorak and Keetongu, Keetongu accidentally fell on the Coliseum's floor, the function was accidentally activated, propelling the floor into random levels.