Ivy (RE2 remake)/biology

Ivy Zombies are human corpses that have been heavily infested with the parasitic seedlings of Plant 43. Whilst their former human status is visible in their general anatomy, the sprouting plants have heavily mutated their bodies. Their body is covered in a thick layer of green vegetation, which coats the skin in irregularly shaped growths. Small vines protrude from their torsos, waving in the air. Large, tumor-like yellow bulbs sprout on random parts of their bodies, which seem to fulfil a vital role to their functionality. Finally, their eyes have dissolved and their head has mutated, splitting vertically in half to reveal a large, gaping maw filled with jagged, backwards-curving fangs.

The yellow bulbs on an Ivy Zombie seem to serve as some kind of primitive nervous system or brain. When these are destroyed by gunfire, an Ivy Zombie collapses on the ground and is rendered immobile. However, these bulbs are not essential to the survival of the plant infesting the corpse, and it will eventually regenerate them, alllowing it to walk again. Only burning the body whilst it is quiescent will destroy the plant matter spread through its tissues and permanently kill an Ivy Zombie. It is easy to recognize when this has happened, as the entire body shrivels and becomes a charred, blackened mass.

This abilitty to regenerate from seeming death unless burned was apparently the cause for many casualties amongst the scentific staff at NEST; a file found in the lower levels of the Greenhouse, titled simply "Somebody's Note", carries a quickly-scrawled warning to any survivors about the need to burn Ivy Zombies to kill them permanently.