The Spreading Spores class feature gives you the ability when Symbiotic Entity is active. Once it is activated, you can conjure up clouds with the Spreading Spores. Circle of the Spores Level 12 ...

Halo of Spores - This reaction deals 1-4 necrotic damage to a target. Symbiotic Entity - This gives you +8 temporary hit points, while boosting attacks to deal extra 1-6 necrotic damage.

Another core feature of Circle of Spores druids is the ability to buff their attacks and hit points using their “Symbiotic Entity” ability.