The Creepateria is an area where monsters eat in a school, and is the monster sons and daughters of famous legendary monsters eat their food and hang out to talk. It is a cafeteria located in Monster High. It is also the Monster High version of the Ever After High Castleteria (though Monster High was a franchise that came first). It is the Ever After High Castleteria counterpart. It is much bigger in the 3D TV specials compared to the Monster High webisodes and webisode-based specials, "New Ghoul @ School" and "Fright On!". It is where teenage monsters, or Monster High students eat and socialize. It is not much available in the book series/book franchise due to the book series carrying a strong portrayal of having a co-protagonist for the normies (humans) named Melody Carver and the fact that the monster children go to school at a humans' school and hide in disguise.
There is no much else known about it, except it might have more information somewhere. There's also the fact that it serves unhealthy foods, which is changed up until the episode, "Creepateria".