A black onyx statuette of a single tentacle with eyes for suckers

The wielder of this artifact may call upon its power to cause any creature to fall unconscious and enter a fearful, nightmarish dream state. At the end of every turn (or every minute if not in combat) they can make a DC 15 CON roll to wake up. They have disadvantage on every action on their next turn as they shake the sleep from their head and they must make a DC 13 WIS check. Upon failure, they attack an ally on that turn thinking them to be from their nightmare. If there is no ally, they attack themselves briefly believing themselves to be possessed by a Great and Terrible Evil.

Upon use of this artifact, the wielder must make a DC 13 WIS saving throw. Upon failure, they become afflicted with long-term madness for 1d10x10 hours.

Long-Term Madness table

This is a God-Touched item