Crown of Thorn

(Acanthasterplanci), it is a star fish that have several caused alarm for the tourism industry because it feds on the cora land the outbreaks of the starfish can eat entire reefs, which take then several years to recover. The predators that keep the pollution of crown of thorn under control . When the Triton was over-collected, to sell it as souvenirs for the tourists, or shells collectors or to put it as a decoration at home...etc. the crown of thorn starfish population reached unprecedented highs, causing significant damage to the reef.    
  The crown of thorn starfish has venomous spines capable of causing extremely painful wounds. This species can grow to more than a spiny arms. Contact with the venomous spines of these creature causes severe pains, swelling, profuse and frequent vomiting, numbers and occasionally paralysis, in some victims, pain has been known to last for several days. The sharp spines are capable of penetrating gloves, boots and wetsuits.     
Immersing the afflicted body part in hot water can reduce the pain, but this not may be practical in some situations. Medical attention is usually required for sever envenomations . In the Red Sea the Crown of Thorns starfish is not as common as in Australia`s Great Barrier reef . Nevertheless, evry once in white single specimens are found on stony corals , their preferred source of food. The fact that the Crown of Thorns starfish deplete large areas of the reef-building stony corals of their polypsby eating them is probably a natural process which cant be influencesd even by healthy populations of its arch-envermy, whish is the giant triton shell, and it is siad this starfish leave behind in its lifetime an area of about 50 sqaure meters of dead white corals skeletons.
The Triton shellfish slides its proboscis under the starfish which is then  devoured from its soft and unarmed oral region at the center, and after about two hours nothing is left of the echinoderm.

text from: RedseaFuntime guide