Rust Monster
What is your strategy for confronting the fantasy creature Rust Monster in Dungeons & Dragons?
More info on this creature: Source 6
If you have an ability to spider climb use that. Get up on the ceiling out of reach and shoot arrows or whatever at it.
Note to Fighters: Carry a wooden shield and an extra weapon.
Obviously getting into a melee fight with this creature can be devastating to armor and weapons. Survey the enviroment and your mundane items for any way to attack this creature from a range.
Ranged, fire and magic attacks are obviously ideal, or even leaping onto it (suitably prepared) and directly using a weapon or even hands to attack it in a tender spot like an eye or throat if possible.
Nearly adorable in their simplicity and non-immediately deadly attacks, it's pretty obvious Rust Monsters were just a malicious meta-game invention to get rid of characters' defenses and weapons to put them in a hard spot, as well as make them spend more gold on buying new equipment. That's the only reason for such a thing to exist, as it has a pretty specific ability - it's essentially a cheat for frustrated GM's that can't throw things at the party as easily as they used to because of improved gear and abilities.
I learned quickly as a fighter to watch for these nasty little creatures. I learned that carrying some leather armor and wooden items can come into great use if you run into them.
Yes as a DM they are very handy to use if you feel the characters are getting strong and powerful. Nothing causes greater stress to characters than to see their weapons and armour gone right in the middle of a dungeon.