Target gets instantly afflicted by Short Term Madness (roll percentile, and then roll 1d10 minutes, and see table) and on a failed Wisdom saving throw, takes 4D4 psychic damage. (On a successful save, the target is only afflicted by the madness and doesn't take any damage.)

Damage increases by 1D4 each level above first.
Short Term Madness increases by 1D10 minutes each level above first.