Blackblood (H)

You transform a portion of your blood into a poisonous substance. As you cast this spell, you must spend a number of hit points. You gain a number of temporary hit points equal to the amount spent. For as long as these temporary hit points last, whenever a creature hits you with an attack while within 5 feet of you they take 1d8 poison damage and become poisoned until the start of their next turn.

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, you gain 5 additional temporary hit points for each slot level above 1st.