Sea urchin
Sea urchins or urchins () are typically spiny, globular animals, echinoderms in the class Echinoidea. About 950 species live on the seabed, inhabiting all oceans and depth zones from the intertidal to . Their tests (hard shells) are round and spiny, typically from across. Sea urchins move slowly, crawling with their tube feet, and sometimes pushing themselves with their spines. They feed primarily on algae but also eat slow-moving or sessile animals. Their predators include sea otters, starfish, wolf eels, and triggerfish.
Toxopneustes pileolus
Nevertheless, flower urchins are still considered highly dangerous. The severe debilitating pain of the flower urchin sting compounded by muscular paralysis, breathing problems, numbness, and disorientation can result in accidental drowning among divers and swimmers. The flower urchin was named the "most dangerous sea urchin" in the 2014 "Guinness World Records".