Celtar's Corrupting Sphere

When you cast this spell choose a point you can see.

A corrupted creature attacks any beings which are hostile towards the caster of this spell

A purplish black sphere appears at the chosen point, and each creature within 25 feet of the sphere must make a strength save or be swallowed up by the sphere.
When a creature is swallowed if it has less than 30 hit points remaining it immediately becomes corrupted. If they have more than 30 hit points they take 30 (6d8) psychic damage at the start of their next turn. If a creature would be damaged this way it may make another Strength save to break free.