Hypnotic Pattern

Hypnotic Pattern can end a fight before it starts, until someone hits the wrong target

At the table. Hypnotic Pattern is a 30-foot Cube within 120 feet. Every creature in it who can see the pattern makes a Wisdom save or is Charmed for up to a minute on your Concentration. While Charmed this way it's Incapacitated with a Speed of 0: no actions, no moving. It snaps out if it takes any damage, or if someone uses an action to shake it awake.

What changed from 2014. The effect is the same. The material changed from incense or a glowing vial to a pinch of confetti. It's still on the Bard, Sorcerer, Warlock and Wizard lists.

What it's worth. At save DC 15 (a level 5 caster with +4), against a group of four:

Low-Wisdom brutes are the dream. Wise casters and priests are where it fizzles.

The choice that matters is what the party does next. The charmed ones are out of the fight, but damage wakes them. Focus everything on whoever saved, then deal with the sleepers one at a time. Tie them up, walk past them, or wake them one per turn and fight them alone.

The common mistake is the Fireball on the next turn. One area spell over the charmed group wakes all of them at once and undoes a 3rd-level slot. The other mistake is the Cube itself: allies who can see the pattern have to save too, so cast it before your fighter charges in.

The human angle. A pattern flashing into existence is exactly what the eye can't ignore. Abrams and Christ showed that the sudden start of motion captures attention by itself, even when the motion has nothing to do with the task. Hypnotic Pattern is that finding turned into a spell: the colours move, every head turns, and the fight stops. Nothing clears a room like confetti.

Source: Abrams, R. A., & Christ, S. E. (2003). Motion onset captures attention. Psychological Science, 14(5), 427–432. doi:10.1111/1467-9280.01458