Astor's Mirror Reflection

You extend your hand, and a barrier of shimmering magical mirrors surrounds one creature you can see within range. Until the spell ends, the target has a +5 bonus to AC, including against the triggering attack. If a spell attack misses the target because of this bonus, or if the target is affected by Magic Missile, the spell is reflected back at the original caster. Use the original attack roll if applicable; otherwise, the spell affects the caster as though it had originally targeted them.

A creature whose spell is reflected can use its Reaction to cast Shield or another applicable reaction spell to protect itself. A spell reflected by this spell can't be reflected again.