Maurice is a small being who has a human head with a cockroach body. He has two yellow eyes with dark bags around them, a mole on his cheek, and his black mustache is divided into two parts. He also has a slight tan. His cockroach body is a reddish-brown color with a orange chest. As a cockroach his body has 3 appendages on each side, and as the capability of flight (as most cockroaches are able to fly). He has long black hair and sharp white teeth. Having a cockroach body, Maurice is able withstand high levels of radiation.
Before swapping with Sydney's body, Maurice was a large muscular man. His arms were immensely robust and hairy while in contrast his legs were short and stout. Maurice's human body wears an orange hazmat suit which has a radioactive sign on the top right. The suit's sleeves are ripped off. The suit is equipped with a hood, large black gloves and small black boots.
Maurice is fairly a calculative man. As a scientist he is very intellegent, but is showboats an arrogant persona. He loves filth and money, despite his digust for Sydney's unusual habits. Maurice doesn't seem to care about the lives of other people, showing his malicious, this can be implied for his supposed interest in insects, thus willingly swapping his body with that of cockroach. When in his fights with Ben, Maurice shows to have very cocky personality, often sarcastically congratulating Ben's intelligence, citing him for figuring out the obvious in his plans, however this ego tends to vanish if he is ever annoyed, infuriated or gets frightened when he can't win or control something dangerous like his Magg-O-Net Monster. He is also a bit clueless since he could not read a map. However despite the numerous loses he quickly regains his composure.
Being highly more intelligent than his partner, he acts as Sydney's superior. As it shows, Maurice seems to have close bond with Sydney. However despite this brotherly act towards his comrade, he often instructs and tells off Syndey for acting either asinine or getting distracted from their main objectives, Maurice acts a slight harsh to Syndey and mocks him for his sensitivity or his minor view points and habits, disgusted by his Cockroach instincts, despite being placed in his body and his interests in insects.
In his debut The Filth he collected piles of garbage and radioactive waste in order create and use the Magg-O-Net to create the Magg-O-Net Monster. When Four Arms destroyed the remote control, he had no control of the monster, so he fled.