The sunlit grappler resulted from a population of colony grapplers floating too close to the surface of the ocean. With the colony grappler already well-adapted to sunlit environments, the errant colony grappler population had an easy time adapting to their new home. After experiencing some change, the colony grappler evolved into the sunlit grappler.
The sunlit grappler has perfected its niche. While its ancestors suffered from a lack of food while outside of a host, the sunlit grappler has been able to take advantage of its newfound photosynthetic abilities. While outside of a host, it will drift through the water column, soaking up sunlight. In order to better orient itself, it has developed a stigma, allowing it to detect light. It will always have its flattest side facing the sun when exposed to light, maximizing the amount of sunlight it can have access to. It will also feed on any stray photosagnians, protoviromoebans, or protopathogenans that come too close to it when outside of a host. Sunlit grapplers are primarily found inside of geletaventrians, and will feed on invading pathogens. When there are no pathogens inside of its host, the sunlit grappler will enter a state of dormancy.