Tyson Daniels PhD's Sacrificial Aura

For the duration, this spell creates a 10' radius Aura around the target marked by glowing sacrificial energy. Any enemy creatures that come within range for the first time or start there turn in the aura must make a Constitution saving throw.  Upon a fail, they receive 2d8 Necrotic damage.  The caster also heals for half of the damage dealt to the 1st target of the spell that turn. on a successful save nothing happens

The damage increases by 1d8 for every level above 2nd, and you can absorb half the damage done from another target for every level above 2nd.