Rust Monster

Origins

The rust monster began, like the Owlbear, in a bag of cheap plastic figures made in Hong Kong. In the early 1970s Gary Gygax was running Chainmail battles on a sand table in Lake Geneva, and he looked through dime stores for anything he could use as a miniature. One bag, labeled "prehistoric animals," held a set of strange monsters. By most accounts they were knock-offs of creatures from Japanese kaiju films and television. Gygax told the story himself, printed in Ed Greenwood's "Ecology of the Rust Monster" in Dragon #88 (August 1984; see The Strategic Review & Dragon). Among the figures was one that "looked rather like a lobster with a propeller on its tail." At first "nothing very fearsome came to mind." Then, he said, "inspiration struck me. It was a 'rust monster.'"

The same bag is credited with several of D&D's oddest creatures. Tim Kask, the first editor of The Dragon, said the umber hulk and the rust monster were Gygax's inventions "to 'explain' two plastic monsters from a bag of weird critters from the dime store." The artist Tony DiTerlizzi, who drew monsters for TSR in the 1990s, later researched the toys and matched them to the rust monster, the owlbear and the bulette, a burrowing "landshark" that first appeared in The Dragon #1 (1976). No myth lies behind any of them. Unlike the Basilisk or the Griffin, these were monsters made to fit the figures Gygax happened to own.

Into the dungeon

What Gygax made of the lobster was cleverer than another thing to kill. The rust monster appeared in Supplement I: Greyhawk (1975), the first expansion to Dungeons & Dragons, by Gygax and Rob Kuntz. It is described there as "inoffensive" but "the bane of metal with ferrous content." Any iron it touches rusts at once, and the monster eats the rust. A sword that strikes it rusts too, and at four times a character's speed it cannot be outrun. It does not threaten the character's Hit points much. It threatens the fighter's armor and the magic sword the player spent months winning. The rust monster attacks the player's investment in Loot & loot tables, and so players remember it with a special dread that critics have noted ever since. One called it "the most feared D&D monster."

The Monster Manual of 1977 gave it its first picture, by Dave Sutherland: a tick-like creature three feet high and five long, with an armored shell, two long antennae and a tail ending in a propeller. It now ate any metal and moved six times faster than an average character. The Dungeon Masters Guide (1979) joked about it too, with a drawing of an armored fighter leaping into a wizard's arms at the sight of a playful rust monster. The creature stayed in the Basic line and the Rules Cyclopedia (1991), and in computer games it found a home in NetHack, where it eats metal as greedily as on the tabletop.

Variations

Each edition changed the rust monster's look or its rules. The second edition Monstrous Compendium (1989) replaced the propeller with a paddle, and the Monstrous Manual (1993) gave it grasshopper legs and feathery antennae. Third edition (2000) reduced its speed to a character's, gave it a feeble bite and rated it Challenge Rating 3. Fourth edition made the bite the thing that corroded metal and let the monster digest magic items into a recoverable "residuum." Fifth edition (2014) returned to the antennae. Variants include the rust rat of the British magazine Imagine (1985), undead rust monsters, and the O-akasabi-same of Dragon #346 (2006). Paizo kept it in Pathfinder and devoted six pages to it in Dungeon Denizens Revisited (2009).

The rust monster's legacy is a design lesson. A monster can be frightening without being deadly if it threatens what players care about. Every later game that sets an enemy to steal gear or break equipment follows the idea Gygax found in a plastic lobster.