The Essence Transfer

You create a link between yourself and one choosen enemy in range. Make a ranged spell attack against this target, on hit creature gets 1d8 necrotic damage, and for the duration whenever you effect him with a spell of level 1st or higher you can regain 1d4 hp as a bonus action. This effect can end early when either you or the target leave the spells range.

At Higher Levels. This spell’s damage increases by 1d8 and its healing to a higher dice (like from d4 to 1d6) when you reach 5th level (2d8 and 1d6 healing), 11th level (3d8 and 1d8 healing), and 17th level (4d8 and 1d10 healing).