It is the common species, Trolliana agitatus; the ready camouflage of the anonmarsh is its natural habitat. What we have here is its bizarre mating dance, meant to attract as many potential suitors as possible, but the Greater Bogtroll will then proceed to mate with none of them at all.
This behavior is poorly understood by science, but fascinating to observe. Despite never finding actual breeding partners, and being the natural enemy of nearly every other species it encounters, it continues to thrive. Some have even theorized that it has some means of feeding upon the energy it provokes other animals to expend. This hypothesis, for years considered a crackpot idea, is gaining wider acceptance.
Trolliana's main predator is the velociraptor, whose love of dining on its flesh is so strong that not even millions of years of extinction can keep it from the hunt.