Fun With Damage Types: Three Bizarre Creatures

Three creatures meant to make less useful damage types more useful and some of the more useful damage types less useful -- not just through resistances, vulnerabilities, and immunities, but through interesting and flavorful effects and abilities.  The eponymous creatures are the following:

• Vascularch -- an aberrational floating heart that uses its veins to fight that is weakened by poison damage.
• Box plant -- a plant creature with a strange leafy shield that deflects most attacks but which may be burned away.  However, this plant is quite full of life and will regenerate if not dealt acid or necrotic damage.
• Eyelasher -- a strange floating eye that uses its optic nerve as a flail and that can shoot beams of light from its pupil -- but it also has another horrorfying secret.