From 2speccers2tools wiki

With the diversification of herbivores on Dingus, it was only a matter of time before predators would evolve to feed upon them. One such group would a population of Nostalgias that moved away from eating detritus and began eating small prey. Over time they would specialize on such a lifestyle and further improve on it, eventually becoming a highly successful group of predators known as the Nostalgithyons.

The Nostalgithyons have re-developed several traits from their ancient ancestors that had been lost for a while, these are the redevelopment of hair, teeth and nostrils. The nostrils help them breath in air so they can have a more active lifestyle, while they also help smell potential prey that is approaching them so they can prepare to strike. The redevelopment of hair provides several different uses, such as helping them to thermoregulate better than their ancestor or most of their relatives. Hair also helps break up the outline of a Nostalgithyon among things like the branches of Canarflora or Nomflora or even the forest floor, allowing them to more easily sneak up on potential prey. The Nostalgithyons can still move like a gastropod in a relatively straight line, but they more often travel by slithering from side to side not unlike that of a serpent. Their hair on their underside have become thick and attached by large muscles at their bases, which help aid them with moving around and holding onto something like a branch. They lie in wait for prey to approach before they strike out and grab the victim with their mouth. This is where the redeveloped teeth come in, as they help maintain their grip on the prey they catch. These teeth are also massive, with the front most ones poking out beyond the lips even the mouth is closed. When hunting radfauna, the Nostalgithyons will grab the prey by the back of the head and twisting them around in such a way that their radiation organs prove useless in defending themselves. The robust hairs on the Nostalgithyon's underside help grip the victim as they throw coils around it and constrict it until it dies. Once it dies, the Nostalgithyon will begin to feed, either by swallowing a small fauna whole or using their teeth to rip off chunks of flesh into chunks small enough for them to swallow. Specific species will often have unique patterns to match specific areas so they can effectively hunt down their chose kinds of prey. While most species live within the forests and jungles, a few species do live within the "Dingus Shrub".

Instead of laying their soft-eggs in water, the Nostalgithyons retain their eggs within their own bodies until they hatch internally. After this, the female will give birth to multiple youngsters which are able to live on their own soon after being born. As they adapt to a changing world, the Nostalgithyons end up driving the local populations of nostalgia to extinction within the jungles and forests of Dingus.