Starfish, also called sea stars, are poisonous to humans. The sun star, the leather star and the crown of thorns are examples of poisonous starfish that cause minor to severe toxicity in the human body.
The crown of thorns starfish is the most common poisonous starfish. It lives on and eats coral. It can grow up to 3 feet in diameter and have as many as 21 arms. This starfish is covered in long spines that can easily penetrate a wet suit. Although its toxin is not deadly to humans, it causes severe redness and burning. In some cases, a person exposed to its toxin may vomit or feel nauseated. The spines may also break off and remain embedded in the victim's flesh.