Zorbo

The zorbo has advantage on saving throws against spells and other magical effects.

The zorbo magically absorbs the natural strength of its surroundings, adjusting its Armor Class based on the material it is standing or climbing on: AC 15 for wood or bone, AC 17 for earth or stone, or AC 19 for metal. If the zorbo isn't in contact with any of these substances, its AC is 10.

Melee Weapon Attack +3 to hit, reach 5 ft., one target. 8 (2d6 + 1) Slashing damage, and if the target is a creature wearing armor, carrying a shield, or in possession of a magic item that improves its AC, it must make a DC 11 Dexterity saving throw. On a failed save, one such item worn or carried by the creature (the target's choice) magically deteriorates, taking a permanent and cumulative −1 penalty to the AC it offers, and the zorbo gains a +1 bonus to AC until the start of its next turn. Armor reduced to an AC of 10 or a shield or magic item that drops to a 0 AC increase is destroyed.