PHB, page 252 SRD

Hypnotic Pattern

3-level Illusion

You create a twisting pattern of colors that weaves through the air inside a 30-foot cube within range. The pattern appears for a moment and vanishes. Each creature in the area who sees the pattern must make a Wisdom saving throw. On a failed save, the creature becomes charmed for the duration. While charmed by this spell, the creature is incapacitated and has a speed of 0.

The spell ends for an affected creature if it takes any damage or if someone else uses an action to shake the creature out of its stupor.