Bane's Psychosis Overload

You seize a creature’s mind and flood it with a torrent of meaningless thoughts while siphoning fragments of useful knowledge.
Choose one creature you can see within range. The target must make an Intelligence saving throw. On a failed save, the creature takes 3d8 psychic damage, is overwhelmed by mental static, and is incapacitated until the end of its next turn. On a successful save, the creature takes half as much damage and suffers no other effect.

When you twist the creature’s thoughts, you glean a flash of insight into its defenses. The DM reveals one of the following traits of the creature (your choice): its damage vulnerabilities or its damage resistances.