The group of organisms found in oceans and using stinging cells called cnidocytes to capture prey are cnidarians.

This group includes animals like:

* Jellyfish: These are the most well-known cnidarians. They have a bell-shaped body with tentacles that contain cnidocytes.

* Sea anemones: These stationary animals look like flowers and use cnidocytes in their tentacles to paralyze small prey.

* Corals: These animals form colonies and use cnidocytes to capture food and defend themselves.

* Hydroids: These are small, colonial cnidarians that can be found in both freshwater and saltwater environments.

Cnidocytes are specialized cells that contain a stinging structure called a nematocyst. When triggered, the nematocyst shoots out a barbed thread that can inject toxins into the prey.