This defenseless-looking sea cucumber has a secret weapon. When under threat, it expels its own guts as sticky filaments that can tangle or injure its aggressor.

These animals may look like boring lumps...but sea cucumbers have all sorts of surprises.

This hairy sea cucumber takes several hours to burrow under the sand.

Its body now safely hidden, it's time to eat.

It unfurls its feathery tentacles.

Any microscopic morsel it finds gets pulled down into its mouth.

A miniature forest of cukes filter the water clean of organic debris.

But at the first sign of trouble...the forest vanishes...to feed another time.

It knows no fear...possibly because it has no brain.

Instead, a nerve ring around its mouth tells it when to move, when to fight, and when to eat.

In the animal kingdom, there's no emergency rooms, band-aids or kisses from mommy.

Fighting takes guts.

For this cuke, that's no metaphor.

A fish nips at its backside...the wrong side.

It expels its guts out of its very own ring of fire.

Their filaments are sticky and toxic.

If the fish gets caught, it might die.

The fish wants no part of this fight...or this surprisingly resourceful lump.