Change the damage reduction to DR 1. This is a buff worth ~1-3
quanta per creature.
I would drop the anti healing effect. It clutters the card. Either that or drop the damage reduction because this card currently is 2 card ideas stapled together.
If you make the effect not stack (for fear of DR 3-6s) then a cost of 6
|4
sounds reasonable for a DR 1 version.