FUNNY you should mention it: The deal with monstrosity is that is was originally envisioned that SE employee would be playing as the monster in some type of popped arena to alleviate teh pressure of the 24 spawn NMs, this was extremely early in the life cycle, but monstrosity didn't arrive until infinitely later.

Monstrosity is still hilarious and a blast but it either needs to be worked into pankration and or have WAY better player sided rewards to liven it up a bit - but it really is its own reward, like sinister reign meta.