I thought of this in another suggestion, and I think it'd be a really great addition to the game. It'd also serve as a way to repurpose the legacy crawler sprite (albeit a touched up, remade sprite).
There would be different variants of skitters, all working together in a colony.
Cave skitter: Makes up the vast majority of the colony, living in small, dry caves to protect the queen.
Queen skitter: Large, broodmother-like skitter that lives in the hearts of colonies. Whenever it rarely leaves caves, it is transported by a swarm of other skitters.
Ocean skitter: Aquatic skitters that have smaller, less developed legs and are better suited to swim. They act as the colony's scouts to find food. These would follow the submarine and occasionally damage the hull. After a certain amount of time, they'd go back to the colony to get a larger swarm of skitters. Upon being attacked, they would try to swim back to the colony and get a skitter guard to help (hence the name skitter, based on the genetic material).
Skitter guard: A larger, hammerhead-sized skitter that would be called in by ocean skitters along with other skitters to help deal with larger threats. They'd have decent armor, and have as much health as a golden hammerhead. In later biomes, there could be multiple skitter guards in one swarm.
I'd love to hear feedback on this idea.