So A) Delta Green.
B) our team was called I to investigate a mysterious disappearance of a measles out reak in a midwestern town. Investigate investigate medicine man. Investigate investigate accidentally discover things (kids eating in unison, syconized cows and wild life) followed by other things (previous settler and evangelist went native has a Bible with crazy stuff about binding a mud demon). Link up with the medicine man who knows the stories, put together some people to do the ritual (breaking dg protocol, but God damn, elder thing escaping).
So we start the ritual, and it is me as the effectively paladin (shooty fbi agent with people skills) and a medical examiner, some old latin americans and the shaman... Swarmed by hive minded small critters, we manage to keep them off the medicine man, but everyone else is forces to defend him or runs away, putting the whole ritual onto him.
We get like a round to catch our breath, and then make a notice check to see a blur of black and white cows stampeding toward us. Me being the fbi agent with the character motivation of protect america from threats at all costs stands my ground and unloads my gun into the press of beef. do a ton of damage but end up unconcous and dying under a pile of cows.
The medicine man finishes the ritual and my partner manages to dig my body out from under a pile of cows, and crit fails first aid. Good night agent Alvarez, you saved the Midwest from a shaggoth.
Bonus points, the milk from the cows was hyper charged by shaggoth juju and was the reason measles went away.