|Also Know As||Closet Monster|
|Hair color||Pink (feathers)|
|Residence||Theo's Closet (formerly)|
Jan Itor's Closet (currently)
|About friendship, interests and family|
Theo Merton Jr.
|Appearance and Voice actor|
|First episode||Monster Stink|
|Last episode||Monster Stink|
|Voiced by:||Christian Potenza|
Stan is a closet monster that's been locked in Theo's closet, ever since he first moved into his house. Being a monster, he is immune to the loop, given that the loop is an entirely man-made concept, as he explains. He first appeared in "Monster Stink".
Ever since Theo and his dad moved into their current house, there has been a mysterious closet that was chained off and supremely locked. Theo's dad has always told him never to go in there, claiming that a monster is trapped in that closet. In "Monster Stink", Theo dropped a pamphlet for Monster Appreciation Day, which slid into the closet, and that Monday at school, Stan showed up, revealing himself to the world. Stan claimed to have never left the closet before because he was just afraid of the humans as they were of him. He then had a lot of fun, playing with Theo and Luc all day. The next Monday, it turned out that because of him being a monster, he was unaffected by the loop, and planned on spending every Monday with Luc and Theo for the rest of time. Luc and Theo didn't like this idea and wanted to get rid of him, only angering him and making him want to eat them. Luc and Theo were terrified of him and so was the rest of the school. So, they had to pretend they liked him. Then, Theo revealed that he wasn't scared of him anymore, claiming that he was much scarier, when he was just a bunch of noises coming from the closet. Stan took this as a challenge and closed himself in the janitor's closet, only to soon realize him mistake. Luc and Theo celebrated not having to deal with Stan again, even in Theo's own home.He is also played by Christian Potenza.
Stan is a giant, furry, pink monster with horns and a yellow beak and orange bird-like legs. He has a tuft of three pink feathers on his head and a patch of pink feathers above his eyes.
Stan is the monster equivalent of an annoying college roommate. He is an unnaturally happy guy, who's very laid back, slobbish, and lazy, and doesn't take anything seriously or with responsibility. However, if Luc and Theo ever denied him his freedom, he would go into an all-out rage mode, revealing his evil side, threatening to eat them. Whenever he does this, he still maintains the same stupid smile as before, due to his delightfully dim-witted nature.