A lion's mane jellyfish washed up on a New Zealand beach.

(Eve Dickinson/Adam Dickinson)

At a Glance

They told their kids not to touch it — whatever it was."It almost looked like a load of muscles contracting," a beachgoer said.

Eve and Adam Dickinson were enjoying an outing with their two children atPakiri Beach, north of Warkworth, New Zealand, when they came across a startling marine specimen.

Adam told that his son observedthe animalmoving:"It's alive."

"It almost looked like a load of muscles contracting," Adam said.

They told their kids not to touch it — whatever it was.

Diana Macpherson ofNew Zealand’s National Institute of Water and Atmospheric Research later the animal as a lion's mane jellyfish, the longest jelly in the world.

For perspective, the blue whale is thought to be the largest animal ever to inhabit Earth. The lion's mane jellyfish can grow 23 feet longer than the largest known blue whale.

A lion's mane jellyfish washed up on a New Zealand beach.

(Eve Dickinson/Adam Dickinson )

The jellies,which have a formidable toxin-loaded sting,are preyed upon by sea turtles. They mostly dwell in the Northern Hemisphere, but have been seen as far south as the .

Children observe a lion's mane jellyfish in wonder.

(Eve Dickinson/Adam Dickinson )