Rampant Games - The DM's Special

The Rampant Coyote's latest post is on "DM specials" - those monsters designed to catch you off guard, such as the classic mimic.  Not my favourite game element but they do add colour to "old school" dungeon designs:

Suddenly - shock and horror! - the chest itself attacks. It is a mimic - a creature which has disguised itself to appear as a treasure chest to lure unsuspecting adventurers to their doom!

Nothing says "Old School RPG" like these kinds of monsters. Ed Greenwood (creator of the Forgotten Realms setting for Dungeons & Dragons) once used the term "DM's Special" to describe these creatures that seemed designed purely to trip experienced players up. While most monsters in fantasy RPGs require you to not think too hard about their ecology or how they might have possibly evolved, these kinds of creatures went beyond the pale in this respect. These things were predators optimized for a world full of dungeons and a steady supply of treasure-hunting adventurers to eat.