So simple, probably already mentioned somewhere.. a dark elixir spell that gives a lump sum of health to troops within a small radius.
This spell would not heal over time, just instantly gives a sum of health to all units within the radius. I think the radius should be smaller than a regular heal spell. The point of the spell would be to give a high hp troop a quick health boost in a pinch without taking up two spell slots.
For instance, you have a pekka taking too much damage and losing health fast and you need it to stay alive just a bit longer, but you dont want to use a heal spell on a single troop. Well you can drop a dark heal spell with one spell slot on it and boost its health back up, maybe 15%-30% depending on spell level.

