The creatures thin double-walled sac is filled with a gelatinous substance. In the center of its boneless body is where the jellyfish digests its food. Its mouth is beneath the bell shape underside where tentacles hang like a shaggy mane. Jelly fish come in all sizes. One of the most common and widely found is the Moon Jelly.
Moons have a bell size of around six to eighteen inches.
In the frigid waters of the Arctic Ocean there is another species called the Lions Mane. These cold water creatures have attained bell sizes of over eight feet across with one hundred foot long tentacles, making it the largest planktonic feeding animal is any ocean. Though most of these planktonic feeders are harmless, the tentacles of some species are extremely dangerous . Sea wasps for example are among the deadliest of sea creatures. Their stinging tentacles are so poisonous they can stop a swimmers heart from beating almost instantly upon contact.