They were clumsy swimmers and preferred to cling to undersea canyon walls, using their antennae to sense for prey that wandered too close. They could live up to 100 years. Kwazel Maws were very similar in appearance to the swamp slugs of Dagobah save for the bio-luminescent markings along their bodies, a fin at the end of the tail, and their much greater size. Their skin was impervious to most laser blasts.
While on a mission on Rodia, Jar Jar Binks encountered a friendly Kwazel Maw, whom he affectionately named "Boogie". This particular specimen seemed to be easily domesticated by Jar Jar, and also allowed clone troopers to approach it. Boogie came in handy during the battle, allowing Jar Jar to stand on its back while it destroyed all the droids in its path, unharmed by their lasers due to its thick hide. It also toppled Nute Gunray's shuttle into the sea, allowing the Viceroy to be captured by the Republic forces. Later the bounty hunter, Robonino, was swallowed by a Kwazel Maw during a fight with Kit Fisto on Rodia. He was later regurgitated by the Kwazel Maw, where he was promptly captured by the waiting Fisto and his troops.