Bizarre alien worm-like creatures infest gigantic barrel sponge

Scuba divers in Papua New Guinea encountered some bizarre creatures on the barrel sponges at almost 33m (100 feet) beneath the waves. They had descended on a wall that shot up from the sea floor thousands of years ago due to volcanic activity. This wall has become home to corals, sea fans, giant barrel sponges, and thousands of animals that live among them.

The creatures were long and white and some stretched out more than a meter (3 feet) in length. They moved slowly over the barrel sponge with a feathery mouth that continually opened and closed. Fifteen tentacle-like appendages moved rhythmically, folding in on the creature's face in slow motion. The animals moved over the surface of the barrel sponge slowly, appearing to be devouring the sponge. They numbered in the hundreds and looked like some sort of worm beasts out of a science fiction horror movie.

What appeared to be an infestation of carnivorous animals eating the giant barrel sponge was actually a collection of sea cucumbers filtering the water around the sponges. These sea cucumbers are harmless to both the sponges and the humans watching them. They move their feathery limbs through the water in a motion designed to catch algae and rotting vegetative debris so that they can draw it into their moves for consumption. These sea cucumbers can grow to more than 2m (6 feet) in length. Their presence on the barrel sponges appears grotesque and threatening, but the sea cucumbers are doing a lot of good for the ocean and the reef on which they live.

Many sea cucumbers are edible and easy to catch, making them a staple food for some of the traditional living communities that make their homes in Papua New Guinea. For scuba divers, a sight like this is a fascinating one, and a reminder that life deep below the surface is mysterious and beautiful. Each adventure into the ocean is a different one.