You wouldn't expect brainless blobs
lurking in oceans across the globe
to be dangerous.
Well guess again.
These animals are literally heartless.
Some can even kill you where you stand.
Or swim.
It's hard to believe anything that is 95% water
can be considered a lethal weapon.
When it comes to jellyfish and their eerily long tentacles,
we've all heard stories of how painful their sting can be.
Agonizing discomfort is one thing,
but injecting toxins able to cause cardiac arrest
is quite another.
Number five.
Kaboom!
Like all jellyfish,
the cannonball variety are missing a heart,
blood and brain.
Despite that,
it's equipped with a central nervous system
that enables it to smell and sense light.
It's also capable of releasing a paralyzing toxin
to immobilize its next meal
and has a sting packing enough of a punch
to cause a heart attack.
Steering clear the cannonball jellyfish.
Number four.
Officially known as Morbakka fenneri.
we prefer it's much cooler sounding fire jelly nickname.
It's only the size of your fist,
but it's tentacles can be up to 1 m (3 ft) in length.
Crossing paths with its stingers in the waters around
Australia
can leave you vomiting
as you endure full-body spasms
while you try to fight off complete respiratory failure.
Think that's bad? You ain't seen, or felt, nothing yet.
Wait until you see number three.
Beware anything named after a lion.
Meet the colorful
all 37 m (120 ft) of it.
The largest jellyfish on the planet
and longer than a blue whale,
it's over 2 m (8 Ft) wide
and can have as many as 1.200 tentacles
engineered to shock their prey to death.
Those tentacles and their neurotoxins can cover
a lot of territory,
even after the lion's mane jellyfish is dead.
Just ask the dozens of swimmers
at a New England beach
who found themselves being stung
repeatedly by a lion's mane jellyfish's floating corpse.
Number two.
the transparent assassin of Australia's oceans.
They're the size of a sugar cube
with tentacles 1 m (3 ft) long.
And these tentacles are laced with tiny harpoons
that deliver deadly venom 100 times stronger
than that of a cobra's in nanoseconds.
This sting is so toxic
its life-threatening after-effects
have been christened
Irukandji syndrome.
There is no known antivenom available,
just a guarantee you're going to be headed to a hospital
hoping your heart doesn't stop pumping.
And finally number one.
It swims faster than you.
It can see.
There are 50 varieties of box jellyfish,
but the most lethal of the bunch
and their 24 light-sensitive eyes
are found around Northern Australia
and the Indo-Pacific region.
How lethal are they?
The paralyzing venom of the sea wasp
jellyfish is powerful enough
to launch a simultaneous attack on your nervous system
and vital organs.
This sends you into almost instantaneous shock,
followed by death within minutes.
Have you had a painful close encounter with a jellyfish?
Tell us in the comments below!
So we can be afraid to go in the water forever.
Just in case you're not spooked
enough about dipping a toe in the ocean,
check out the Crazy Creatures episode on
this dangerous siphonophore better known as
the Portuguese man o' war.
It might look like one
thanks to tentacles that reach lengths
of nearly 30 m (100 ft),
but this beast that can travel in groups of nearly 1,000
isn't a jellyfish.
But guess what?
It still stings!
They come in all shapes and sizes,
plus pack enough venom
to kill you before you're done watching this episode.
That's why these jellyfish