Kinorhyncha are an unusual animal phylum sometimes called mud dragons.
That name might be a little over-dramatic for what these animals actually are. They pretty much consist of a head, single segmented midsection and an 11 segmented abdomen. Their body is covered in little spine like protrusions which they use to propel themselves through the mud. Not much is known about this obscure phylum, but they crawl about in the mud eating microbial lifeforms.
Kinorhyncha can be found in the benthic layer of fresh or salt water ecosystems all over the world.