how do you know something is a cnidarian
Cnidaria Cnidarians form an animal phylum that are more complex than sponges, about as complex as ctenophores (comb jellies), and less complex than bilaterians, which include almost all other animals. However, both cnidarians and ctenophores are more complex than sponges as they have: cells bound by inter-cell connections and carpet-like basement membranes; muscles; nervous systems; and some have sensory organs. Cnidarians are distinguished from all other animals by having cnidocytes that fire like harpoons and are used mainly to capture prey. In some species, cnidocytes can also be used as anchors.[9]
Ring-necked snake Its dorsal coloration is solid olive, brown, bluish-gray to black, broken only by a distinct yellow, red, or yellow-orange neck band.[6][7] A few populations in New Mexico, Utah, and other distinct locations do not have the distinctive neck band.[6] Additionally, individuals may have reduced or partially colored neck bands that are hard to distinguish; coloration may also be more of a cream color rather than bright orange or red.[7] Head coloration tends to be slightly darker than the rest of the body, with tendencies to be blacker than grey or olive.[7] Ventrally, the snakes exhibit a yellow-orange to red coloration broken by crescent-shaped black spots along the margins.[6] Some individuals lack the distinct ventral coloration, but typically retain the black spotting.[7] Rarely, do individuals lack both the ventral and neck band coloration; so the use of those two characteristics is the simplest way to distinguish the species.[6]