Halimeda Crab

Huenia heraldica

It's a plant! It's a crab! It's...

Both.

Image: Daniel Kwok

Halimeda Crabs are delightful, little crabs found all around the Indo-Pacific, from Japan to Australia to Hawaii. They're only about 3 cm (an inch) long which unfortunately makes them a crunchy, tasty snack for far too many predators.

Something MUST be done!

Image: Moorea Biocode

Luckily, Halimeda Crabs come with a few useful somethings already. Things that allow them to go unnoticed among the green, leaf-type-things of Halimeda algae.

The most immediately obvious of these things is their lovely, green colour which matches Halimeda perfectly. Good start! Then there are the strange flaps and sticky-out bits on their legs and body that match Halimeda's leafy segments. Nice! Many creatures would leave it at that, but not the Halimeda Crab. They use their head,,,

Video: liquidguru

The Halimeda Crab will now pick up a piece of authentic, honest to goodness Halimeda and attach it to his head. It's the perfect final touch! Now he can walk around and even fall over like a complete buffoon (at the slightest current if he's particularly ambitious about the size of algae he wants on his noggin) and he just looks like a bit of algae because he partially is a bit of algae.

AND he's turned himself from a crunchy, tasty snack to a crunchy, tasty snack with a side dish of algae. And no self-respecting predator wants that.