Cnidaria
Cndaria comes from, greek word "Cndios" (stinging nettle)
Requirements to be considered a cnidarian...
1: You have to have radial symmetry
2: YOU MAY NOT HAVE a heart, lungs, brain, nerve cells, or an anus...BUT MUST HAVE a mouth surounded by a crown of tentacles that have stinging cells called Nematocysts
#: ALL CNIDARIA'S ARE CARNIVORES:)
Fire Coral
Fire coral is a type of cndaria they get their names from their painful inflictions on divers.
Austrailian Jelly fish
These are the most DEADLY/VENOMOUS jellyfish on the planet.
Turtles are not affected by the jellyfish at all, because of their hard shells and thick skin, only part that can possibly be stung is their eye.
Portuguese Man o' War
More Requirements
another thing you must have is a body wall made from two layers, (ectoderm and endoderm) separated by a jelly-like layer called the Mesoglea.
Also, go through through the process of a dimorphic life cycle.
Portuguese Man O' War Stings
Fire Coral Stings
BOX Jellyfish - The Most Dangerous Sea Creature