There’s a reason the ocean is full of jellyfish.

These creatures have mastered the ability  to multiply themselves again and again.

Adult moon jellies grow to  the size of dinner plates.

A mature jellyfish like this is called a medusa   for its resemblance to the ancient  Greek monster with snakes for hair.

But instead of snakes, this medusa has  stinging tentacles that paralyze its prey.

It’s hard to tell by looking at them but  there are male and female moon jellies.

The males release sperm into the water.

And the females collect it  to fertilize their eggs.

Those eggs turn into larvae called  planulae that mom sends out into the world.

They look like fuzzy little potatoes.

Each planula does its best to settle  on something solid -- like rock – and   develops into this, a polyp the size of a pea.

The polyp clings to the rock with a sticky foot,   like a miniature version of its  colorful cousin, the sea anemone.

Its stinging tentacles catch prey that  float by, like these tiny crustaceans.

With each mouthful it grows.

See that budding out of its side?

It's a little clone!

After a few days the clone pops  off, and settles in right next door.

The polyps make more polyps.

And more … Until they form a whole neighborhood of clones … So how do they go from tiny polyp stuck on a rock  to giant medusa gliding through the open ocean?

When the water begins to cool at the end of  summer, they go through yet another change.

They slow down, stop hunting and  develop these ridges along their sides.

Over a few weeks, the ridges  get more and more pronounced,   until the polyp looks like a stack of pancakes.

Each individual pancake, called an ephyra, is a  clone with the potential to grow into an adult.

That’s right, it's a whole extra  round of cloning called strobilation.

It begins with a twitch.

The ephyrae flex and convulse.

They impatiently work to free  themselves … from themselves.

The next ones in line can’t  wait for their turn either.

So they help push things along.

After all that effort, the ephyra  on the very end finally breaks free.

Sometimes jellyfish are so successful that they  explode in number, creating a jellyfish bloom.

That’s great for predators like  barnacles that snatch them up   when they’re young ... and for sea  turtles that scarf down the grown-ups.

That’s why moon jellies play the odds.

By making babies that clone themselves,