How do nematocysts help some animals get food?

Cnidocytes or namatoblasts or cnidoblasts are called stinging cells. These are concentrated around mouth and on tentacles. These help in paralyzing and capturing the prey or killing the enemy.

Each cnidocyte acts as a capsule and encloses a nematocyst. The nematocyst is filled with poisonous fluid, hypotoxin, and its anterior end is drawn out into a long hollow thread which may bear spines.

On being stimulated, the nematocyst is ejected and its long thread either injects poison into the body of prey, killing or paralyzing it, or coils around it.