Disruptive Displacement

You attempt to briefly teleport a creature in the process of making a melee weapon attack so that it hits something other than its intended target.

When you cast this spell, choose an unoccupied space you can see within range. The target is teleported to this space, returning to its original position a split-second later. It must also make an Intelligence saving throw, and may choose to fail if it wishes. On a failed save, it makes its melee attack against whatever creature or object is now in the same position relative to itself as its original target. On a successful save, the target makes the attack as normal.

You may cast this spell after seeing an attack roll, but not after the DM announces whether it hits.