The Mithril Plate Mail of Celeborn (-3) [35,+25]
+4 strength, charisma. Provides resistance to acid, lightning, fire, cold, dark, disenchantment. Cannot be harmed by acid, electricity, fire, cold.
When activated, it removes all non-unique monsters represented by a chosen symbol from the level, dealing you damage in the process. Takes 500 turns to recharge.
Min Level 40, Max Level 127, Generation chance 33, 25.0 lbs

(Angband 3.1.2v2)