Nevertheless, there are a few creatures of which to be aware. These bristles penetrate the skin easily and cause intense itching and sometimes infections. Bristles should be removed with forceps and a local anesthetic and ointment may be applied. Sea Urchins Sea urchins, along with heart urchins and sand dollars, belong to the class Echinoidea, which is in the phylum Echinodermata. Echinoids possess numerous spines, which are used for locomotion and defense, and pedicellariae, tiny, pincer-like structures which are used in feeding.
Some urchins have venomous spines which can cause severe pain.
Repeatedly punching the area with a fist in order to break up irretrievable spines may also help. Hot water will help break down toxins. Fire Corals and Stinging Hydroids Fire corals and hydroids are organisms belonging to the class Hydrozoa, in the Phylum Cnidaria. Most cnidae are stinging cnidae called nematocysts. Fire corals are not actually true corals, but rather are known as hydrozoan corals.