From 2speccers2tools wiki

Although previously a very minor presence in the oceans, soopyfauna are poised to soon become one of the most diverse single clade of marine fauna on 2s2tworld, with new forms evolving to take advantage of any available niche. For the Sweeplet genus, they have easily found their place as benthic suspension-feeders.

The Sweeplets can trace their ancestry to a population of a certain Squigglet species that utilized an additional function of their elongate sensory seta - it can sweep through the water to catch plankton. With successive generations, the implement has become further specialized for a feeding role, growing proportionally longer and broader to maximize range and developing feathery projections to accentuate its surface area. Of course, enough changes accumulated to the point that this population has become genetically distinct from their ancestry; and from there they radiated even further - spreading to nutrient-rich shallows all throughout 2s2tworld. The namesake feathery antenna of the Sweeplets, well… sweeps. Sitting high and plume hoisted into the water, plankton is easily strained. When a Sweeplet has caught enough of a meal, it inserts this implement into its mouth, then reels it back out once the catch is ingested. While the main function of the antenna is to aid in food-capture, it is still useful as a sensory organ - hoisting up also to keenly detect chemical signatures, and if indicative of plankton, the organism will promptly convene towards the source. When not in use, the antenna is folded on the organism’s back. Nuclear Laxative Poopycells are a notable presence within Sweeplet guts, markedly more so should that host species’s diet consist primarily of radioactive plankton.

Sweeplets are otherwise skittish critters; being so scantily defended, at the slightest sight of danger, they disappear into the substrate. Due to this, Sweeplet activity is greatest during the darker hours, when much of their predators are asleep. Their senses are accordingly quite fine, deriving as much potential information on predator proximity as they could. Two pairs of large eyes on the tops of their heads can precisely discern shapes from the environment, while a lateral dual pair is keen to differences in light intensity - to many species, intense sunlight means danger. If their sight fails, subtle setae sensitive to vibrations in the water that rim Sweeplet dorsal sides make up for this, interpreting any unusual movements as predator activity.

Sweeplets retain their ancestry’s locomotory setae, helping to push against substrate particles or scale firm surfaces as the soopy’s body undulates and contracts. During particularly depleted conditions, Sweeplets shift to a diet more reminiscent of their ancestry, rasping at any organic matter they locate. Conversely, in conditions of plenty (such as plankton blooms), they often convene to a single location to partake in mating, linking up gonads to exchange genetic material. Eggs are then deposited into the substrate, and eventually hatch into Soopyworm-like larvae, which themselves are plankton.

Sweeplet diversity is impressive, species taking on a number of forms and lifestyles, and can be found in a variety of ecologies. In the dense groves of Arboralp forest, Sweeplets situate on poopy blades and often sport an ochre coloration, whereas species found in the shallows assume the color of the substrate and surrounding biofilm. As cooler waters tend to be more productive, Sweeplet biomass there is slightly greater than in the tropics. Deeper-water species supplement their diets with detritus more frequently and occasionally their feathery antenna can obtain marine snow, and compose much of the genus’s larger representatives.