Muninn has black skin and a frog-like body, with a short tail at the end and a head shape similar to a tapir. He also has red eyes. He is capable of sprouting bat-like wings.
Compared to Baron Draxum, Huginn and Muninn are relatively dim-witted. Muninn in particular is the most idiotic of the trio.
He came into conflict with the Turtles and April O'Neil during Baron Draxum's first battle with them. Despite the destruction of Draxum's home base, both Huginn and Muninn escaped unhurt.
They later encountered the Turtles again in Big Mama's sporting lounge, where they were watching the Battle Nexus fights. Learning of the Turtles' pursuit of the Oozesquitoes, they alerted Draxum and accompanied him to the battle with Big Mama.
Muninn's retractable wings enable him to fly.
Big Mama: He spends time in her hotel and watches the Battle Nexus matches.