The flutterworm evolved as a result of young wormstems failing to mature. This resulted in a neotenic population of long-bodied free-ranging wormstems. Competition with various asterzoan species forced the ancestral flutterworm into the water column, where it adapted further into the organism we see today. They have spread all across the Vailnoff ocean as a result of their pelagic lifestyle.
The flutterworm is well adapted to its pelagic lifestyle. Its thorn-like spikes have become broad paddles that undulate to provide propulsion. This gives the organism the appearance of fluttering gracefully through the water column. Its mouth has become much wider to accommodate its newfound taste for plankton. It will swim through the water gulping up everything in its path, with its modified antennae directing water into its maw. While filter-feeding is its primary means of obtaining nutrients and energy, photosynthesis sill plays a major role in its feeding behavior. The flutterworm’s body has become dorsoventrally compressed, increasing its body’s surface area, with the flutterworm’s broad paddles only adding to the surface area. The flutterworm will swim close to the surface, using its simple, light-detecting eye to determine its orientation and depth. Because its underside never was exposed to sunlight, the genes for photosynthetic pigment have been selected against. In its place is a pale blue pigment that makes the flutterworm hard to see from below, protecting it from potential predators.
With it now taking to a pelagic lifestyle, the flutterworm’s nervous system has advanced in order for it to interact with its surroundings. It now has a noticeable ganglion in the head along with a nerve cord running down the dorsal side of its body. The nerve cord terminates at the end of the body with it splitting in two and leading into the caudal antennae. These antennae can detect vibrations and alert the flutterworm when another organism is nearby. Its cephalic antennae are lined with chemoreceptors, allowing it to acknowledge the presence of microbial clouds and suspended waste.
Because the flutterworm descended from neotenic wormstems, they lack an adult form. As a result, their reproductive behavior is much simpler. Flutterworms will produce the same ratio of sperm and eggs throughout its life. However, in spite of this simpler mating behavior, many things remain unchanged, including their bicellular gametes and hermaphroditic physiology.