The emperor sea strider is an immense life form from the book Expedition, and the discovery channel program, alien planet. In the book and movie, they live in and around the region known as the Amoebic Sea, a huge symbiotic colony of animals trapping water inside their bodies. Emperor sea striders feed simply by walking on the surface of the sea and do so by biting and swallowing chunks of it with mouths on the bottom of their feet. A group of short, glowing tentacles trails down the lower parts of their bodies and do not seem to serve any important function. While walking they emit waves of sonar, like every other complex organism on the planet. Its young are small flyers that orbit an energy source below its head. Despite their immense size, they are not without predation, according to one account a sea strider was killed by a group of skewers. In the alien planet program, Ike encountered them by chance while getting caught inside of a huge storm of minerals and clung to a rock in the middle of the sea. He detected some very loud roaring and sent a disk to investigate. He discovered them and followed them while searching for leo.
They move by walking on 2 legs with mouths on the bottom of their giant feet. It uses the mouths to bite on the sea.
Sea striders begin life as aerial creatures with fluttering wings who look completely different compared to adults: nymphs have wings, smaller shorter legs which cannot support their weight and contrary to their parents, are preyed on by the very sea the adults feed on, though whether or not the young also feed on the sea is a mystery.