Lion's mane jellyfish

Lion's mane jellyfish ("Cyanea capillata"), also known as "Hair Jelly" and "Sea Blubber", are a type of jellyfish which are mostly found in north Atlantic and north Pacific waters. The stings of these jellyfish are painful but not fatal. The species is found near the coast of the U.S. shore line.
The lion's mane jellyfish can grow up to 2 m width by its pileus ("bell") and its tentacles up to 30 m long. The largest Lions Mane Jelly recorded was 120 FT, but most jellyfish are far smaller, usually some 30 cm by pileus width and up to 50 cm by tentacle length. It eats mainly plankton and is itself eaten by sunfish, sea turtles and some seabirds. Like all jellyfish, it lives only for one year.
A group of jellyfish is called a "smack".