Dance Till You're Dead

You begin a macabre dance, drawing upon the powers of death to enhance your movements. During the spell's duration, you can perform a dance as an action, causing all creatures within a 15-foot cone in front of you to make a Dexterity saving throw. On a failed save, a creature takes 4d6 necrotic damage, and half as much on a successful one. Additionally, creatures that fail their save have their movement speed halved until the start of your next turn as they are momentarily entranced by the spectral dance.

The damage increases by 1d6 for each slot level above 3rd.