Undead Stun Grenade

You create a small but powerful ball of life energy that you can throw anywhere up to 60 feet. Once it hits its target, or hits the ground, it explodes in a 10 foot radius sphere. Any undead creature(s) caught in the blast must make a constitution saving throw. If they succeed, nothing happens, but on a fail they are stunned for 1 round. If the target is not undead, this spell has no effect. 

At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, you can create one additional ball of life energy for each slot above 4th.