Monsieur Mallah first appears in "Homecoming Part 1" and "Homecoming Part 2", where he first attacked the Doom Patrol. The Brotherhood of Evil's first plan was foiled by Beast Boy. The member of The Brotherhood of Evil gathered several villains from previous seasons, including a few new villains to plot revenge and capture the Teen Titans, even new heroes.
In the episode "Hide And Seek", Mallah was sent to kidnap Melvin, Teether, and Timmy, the three heroic kids that Raven was protecting. He attempts to get away in a vehicle armed with lasers, but Melvin's imaginary (but now visible) friend, Bobby the bear arrives to attack and defeat the villainous gorilla, forcing Mallah to retreat.
In the final battle in "Titans Together", Mallah attempts to get away with The Brain, but Robin and Beast Boy stop them just in time. Beast Boy finished him off and in the end, he was frozen along with the other frozen villains and his gang.
Powers and Abilities
Monsieur Mallah's most remarkable attribute is his genius-level intelligence and his capability to think and speak like a human. Mallah is trained in various intellectual areas as well, including electronics, physics and tactics.
As for his physical abilities, he possesses a gorilla's natural strength and stamina, possibly greatly augmented by the Brain's tampering, which, along with his cunning, allows him to take down a wide range of superpowered opponents. While fighting against the Titans, Beast Boy shapeshifts into a gorilla and the two expel equal force on each other.
It is unknown if he was genetically enhanced to speak.