The Choomahviathan (also known as Choomah Island) was an enormous Choomah. Formerly an Island in the South Pacific, it became a living organism when Clarence dropped his contagious experiment down a pit after crashing on the island. Over time, the island mutated into a monster similar to the ones that destroyed Kingdom Cum. Hundreds of smaller Choomahs where created by the experiment as well, taking refuge in the pit (now referred to as the Choomah Hive). The Choomahviathan remained dormant, until Leslie Mackeral and his gang attempted to destroy the Choomahs for good. After the Choomah army was defeated, the Choomahviathan awoke and attacked. After crushing Daednu with it's hands, it attempted to kill the gang, but was destroyed by Clarence with a SasM8, ultimately sacrificing himself in the process.