Are your players running roughshod over your monsters and ransacking your dungeons? Are they disrespecting you as a Dungeon Keeper?
DungeonCo here to help, with the handy dandy Wings of Wondrous Power
A weapon of war created by an extinct race, this rat appears normal but is a simulacrum - beneath it’s mangy fur is a body of bronze. Commanded by words in a lost language, wherever it goes a virulent and lethal plague follows. The cure is similarly obscure.