Megaton Mashup is the new cooperative version of Monsterpocalypse. Privateer Press is going to be regularly coming out with new scenarios for you to try out based on the different monsters in the game. This time around, it's Gorghadra's turn to cause some mayhem in the streets.
From the article:
Last week, we shared a tailor-made scenario for Incinerus in all his fiery glory. This week, we have a what-if scenario of Gorghadra being “accidentally” empowered by a scientist.