Trick Room

You warp space and time around you, reversing the order of battle. 

This spell only works during Combat. Until the end of Combat, Initiative rolls are reversed. The creature with the highest Initiative swaps Initiative with the lowest, the second-highest with the second-lowest, and so on. If one creature falls directly in the middle, its position in the order is unchanged. 

Events that happen on specific Initiative counts, such as Lair Actions, are unaffected and do not switch.