The Forever Exile

You attempt to send one creature that you can see within range to another plane of existence. The target must succeed on a Charisma saving throw or be banished.

The target must succeed on a Charisma saving throw DC 30. On fail, the target is banished to another plane of existence for a thousand years in whatever dimension you were in, but it only feels like a few days to the banished creature. On a success the target is still banished, but will return to wherever it was before the spell was cast on it after whatever number of days the target had over the 30. Example, target rolls a 32, it returns after 2 days.