Careless Whisper

A bard with a saxophone (no substitute instrument can be used, must be a saxophone) can cast Careless Whisper as an action. To hit, you roll a 1d20 plus your performance modifier and your proficiency modifier, if proficient in the saxophone. On a successful hit, the target takes 1d8 plus your performance modifier and your proficiency modifier, if proficient in the saxophone, damage, or is very distracted (because they're dancing too hard) for 1d8 plus your performance modifier and your proficiency modifier, if proficient in the saxophone, rounds and must roll everything at disadvantage for those turns. The target(s) must make a WIS saving throw.

The number of rounds distracted can be spread to other targets in the 50ft range. For example, if you roll a 9 on a 1d8+performance modifier+proficiency, either one target can be distracted for 9 turns, or 3 targets can be distracted for 3 turns, or 2 targets can be distracted for 4 and 5 turns, doesn't matter. However, if you choose to roll to take damage instead of to distract, all the damage goes towards one target. 

At higher levels, the 1d8 die increases by one. At 1st level, 1d8. At 4th level, 2d8. At 8th level, 3d8. At 12th level, 4d8. At 16th level, 5d8. At 20th level, 6d8.