Dak's Comet

You utter the name of a creature you can see, and throw the snowball into the air. The snowball flies into orbit, growing miles wide and forming an icy tail as it transforms into a comet. The target must make a Charisma saving throw or be banished onto the comet as it travels. The cold surface of the comet freezes time, so that it's inhabitants don't age and don't need to eat, drink, sleep, or breathe.

The comet remains visible from your home plane for 2d6 nights every time it appears, before fading to the astral sea. While the comet is visible, a creature that can sea the night sky can cast wish to allow the inhabitant to repeat their saving throw against the spell, returning to their home plane on a success. While the comet is drifting through the astral sea, it can only be accessed by astral projection or gate.

The comet becomes visible again on a cycle of 10d10 years. Whenever the comet returns, you may cast wish once for free. If you use your wish to release the inhabitant of the comet, they automatically succeed on their saving throw, and you suffer none of the stress of casting wish.

The comet orbits even if the target succeeds on its saving throw. If a creature casts dispel magic at 9th level while the comet is visible and uninhabited, the comet leaves to the astral sea for eternity.