If the creature tries to use teleportation or interplanar travel to leave the cage, it must first make a Charisma saving throw.
An unwilling creature must succeed on a Wisdom saving throw to resist this spell. You teleport each affected target to an unoccupied space that you can see within 120 feet of you.
The target must succeed on a Constitution saving throw (the target can choose to fail), or the target is teleported to an unoccupied space of your choice that you can see within range.
But Forcecage seems to be written as though the one doing the teleporting is the caster.
I can see three options for a caster trying to get somebody out of the cage:
- The caster makes the charisma save, as it's the one doing the trying, regardless of whether they're in the cage or not, despite not trying to leave themselves.
- The teleportee makes the charisma save, as their the one being teleported, even if they didn't cast the spell.
- Nobody makes the save, as the wording of Forcecage doesn't prevent this from happening
Is there anyway to figure out which of this is the correct option/most well supported?