Dum's Backup Aura

Abjuration magic radiates from you in an aura with a 30-foot radius. Until the spell ends, the aura moves with you, centered on you. When you or another creature you can see inside the aura fails a saving throw, you can use your reaction to add your spellcasting ability modifier to the roll. Additionally, you can use a bonus action to cause one creature in the aura to gain 1d6 + your spellcasting ability temporary hitpoints for the duration.

 

At Higher Levels: When you cast this spell using a spell slot of 5th level or higher, the radius of the aura increases by 10 feet for each slot level above 4th