Monsters can take any form imaginable, but are universally terrible and powerful; they frequently combine elements from Lovecraftian cosmic horror (existing outside of normal dimensions, unnatural physiology etc.)

They do not need to eat, drink or breathe, instead feeding on the emotional connections between human beings - especially children, with whom monsters form special bonds.

It's mentioned that the world at large is aware of monsters, but because they are so good at remaining unnoticed children are usually the only humans with whom they interact.

Monsters do not have regular stats and skills; instead points, each worth five dice, are allocated directly to body parts which can be used to Attack, Defend or do Useful Stuff (movement, senses etc.).

Dice allocated to a body part can be sacrificed to gain special attributes; these include adding extra basic abilities (so the same body part can both Attack and Defend), adding more useful abilities, improving damage, defence or speed, or allowing one die from the pool to be set by the player (before or after the roll, depending on the dice spent on this quality).

Creator Baugh wrote The Dreadful Secrets of Candlewick Manor, a campaign sourcebook which presents an alternate take on the basic setting, and Bigger Bads, an expansion which adds additional options for monsters.