Monster Beach - Season 1 Episode 42 Monster Nerd Out

When Jan and the monsters discover that Dean is playing a secret roleplay game with his secret friends, the monsters decide to join in. Jan sulks off, wounded at being excluded, while the monsters wreak havoc on poor Dean's game. As Dean's frustration at the monsters grows and his friends respond in abject terror, Jan realises that sometimes it's good to try and join in other people's hobbies, so long as you play by their rules.