Collotheca is a genus of sessile rotifer. As it emerges from its protective sleeve, extremely long hairlike cilia extend outward. Ripples along the cilia guide and sweep food into the rotifer’s mouth. After reaching the jaw-like trophi, food is ingested in a violent, spasmodic action.

It’s strange to me that organisms seem to swim directly into Collotheca on their own, and I have to wonder what the underlying mechanism is that lures them so easily to their death.