Jun 18
Weapons striking a rust monster are affected as if touched by the creature's antennae, immediately rusting or corroding and falling to pieces (Roger Raupp, from Best of The Dragon, TSR, 1980). This accompanied the short story "Excerpt from an Interview with a Rust Monster" by Michael McCrery, told from the perspective of an NPC in the author's campaign who had been polymorphed into rust monster form, orginally published in Dragon 14, May 1978