Sentry's wrath

The Sentry's wrath is a special crossbow that shoots out a slow moving bolt of lightning which shoots out arcing particle streams in random directions until it strikes something. Once it does, that bolt of lightning explodes.

It comes enchanted with Piercing VI and Mending, but also with a cooldown, indicated by an auditory clue. If you shoot before that sound, you will be electrocuted and badly hurt.

Location
The Sentry's wrath can be found in a special room with a copper mechanism and captured Sentries in the Forbidden castle.