Cataclysm Collapse

When you cast this spell, a large 15ft square black hole appears at the point you chose. Up to 9 creatures, besides you, within 60ft of the must make a Strength saving throw. On a failure, they are dragged into an empty square of the black hole square and remain there until the start of your next turn. While in the black hole, their speed becomes 0 and become prone. At the start of your next turn, the black hole collapses, dealing 10D10 force damage to all the creatures stuck inside the black hole. Furthermore, the creatures outside of the center of the black hole square are pushed 15ft diagonally from their initial position and are knocked prone again.