Erevan's banishment

You attempt to send a creature that you can see to another plane of existence.

The target must then make a charisma saving throw or be banished to a harmless demiplane. Then as a reaction, a number of creatures friendly to the caster (not including the caster themselves), equal to half the spell's level (rounded down), can choose to travel with the banished creature.

While in the demiplane, the target of the spell is under the effect of the restrained condition. The allies of the caster do not have that limitation though, being able to move around and take actions as normal. The spell ends early if the target dies or the caster chooses to end it.

At higher levels: When you cast this spell using a spell slot of 8th level or higher, you can target one additional creature for each slot level above 7th.