Blooming Shield

You form a spectral flower around you, letting it bloom and infusing you with its vigor and vitality. Upon casting the spell, you gain 15 temporary hit points. While you have these temporary hit points, an aura of potent pollen and spores subsume you. Any creature that enters within 10 feet of you, or starts its turn there must make a constitution saving throw, taking 5 poison damage on a failure, or 2 poison damage on a success

When cast with a higher level spell slot, you gain an additional 10 temporary hp, and the damage increases by 5 for each spell slot above 1st