I got some monster ideas.  Probably may conflict with your own direction since I like the idea of this RP being absurd as possible more than anything grounded in reality in any shape or form beyond internal consistency.  Really i'll be so annoyed if people make characters who actually know what they are doing because that is so not what this RP needs.

-Pink slime

It's unknown where the pink slime came from.  It may have seeped in from another dimension, it may be something Daedalus made because it wanted to.  The facts of its origins are not important either way.  What is important is that these monsters are extremely hazardous to your health and well being because the pink slime are globs of grounded meat that aggregate into larger and large floods of meat.  Due to being unable to digest prey simply smother and suffocate food with their sheer mass much like a massive, C grade quality meat ameoba.  The meatiness of the pink slime however, may make it good food.  Shame no one really knows what's in it after everything it has eatan thus far.  The pink slime notably has large, cartoonish googly eyes that it uses for decoration more than anything else and all sorts of teeth and bones it prods about the playplace with.  Sometimes it spits these bones at its food to slow them down, as the bones tend to be all mushy and greasy.  Oh god all the grease this thing leaves around.  It's horrible!

-Big boys

Savages who eat their fafo regularly grow up to be big boys who are nice and strong.  Big boys tend to just want friends, but also have a bad habit of eating their friends whenever they get hungry, so hopelessly gluttonous that any sense of free will in their diet has been long lost.   Big boys have to crawl everywhere and often are unable to enter some parts of the play place limiting them to certain 'regions' where they can move about.  They like ball pits and tend to make lairs in them.  Also these lairs smell horrible.  I'm honestly amazed how everyone hasn't gotten cholera yet in this place.

-Mascots

Savages wearing large, bulky costumes who run around trying to entertain people in the only way they know how or claiming they are trying to find help.  Some of them are pedophiles, others are actually furry cosplayers while others still are very unfortunate employees who just wanted to get a living. Either way, you should kill anyone who goes around dressed up in some suit because they very well could be a savage and you'd never know.  Some of them droll grease and shout slogans for fast food places that don't even exist, those mascots are much more dangerous and should get a supersized death for only $1.99.