Bites The Dust

You send forth a 1-inch diameter sphere of dark energy into a living humanoid within range, turning them into your unwilling saboteur. Choose one creature that is a humanoid. That creature must succeed on a Wisdom Saving Throw, or be charmed by you until the start of your next turn. The charm has no effect on undead, constructs, or non-bi-pedal creatures, and those of Celestial descent makes this save with advantage.

A creature that's charmed by you in this way uses its full movement on its turn to run into a space that is crowded with at least 5 other creatures, other than you and your companions. If it's movement isn't enough to reach the nearest crowd, it takes the Dash Action to get as close to the crowd as possible.

At the end of it's turn, if it either reaches the crowd, or gets as close to it as possible, dark cracks form around it before exploding in a violent plume of dark mist. All creatures within 10ft of the charmed creature must succeed on a Constitution Saving Throw, taking 10d6 Necrotic Damage, or half as much on a success. The creature that was charmed in this way takes this damage automatically.

If the target of the charm passes its Wisdom Saving Throw, the sphere phases out through the back of the target, and flies towards the nearest crowd for a number of feet equal to five times your spellcasting ability modifier before detonating.

When you cast this spell using a spell slot of 4th lever or higher, you can target one additional creature for each slot above 3rd. The creatures must be within 30 feet of each other when you target them.