Gremlin

The gremlin can pinpoint, by scent, the location of refined or unrefined aether within 30 feet of it.

Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 5 (1d8 + 1) slashing damage.

The gremlin drains aether from an aether-powered device it can see within 5 feet of it. If the object isn't being worn or carried, the touch automatically drains aether. If the object is being worn or carried by a creature, the creature must succeed on a DC 11 Dexterity saving throw to keep it out of the gremlin's reach.

If the aether-powered device grants any bonus (to attack rolls, damage rolls, Armor Class, and so on), that bonus is reduced by 1. If the device has charges, it loses 1 charge. Otherwise, it stops functioning for 1 round. Left unhindered, a gremlin can completely destroy an aether-powered device.