Shadowrun Apocalypse, Just some ideas. Options

[Tashiro]

Just saw another trailer for World War Z, and I've been trying to think of how to do some sort of event similar to this in Shadowrun. I don't want to go full-scale epidemic, but I'm considering the idea of picking a city, having the event occur, having the PCs in the middle of it, and having them try to escape as the city goes under quarantine. Or perhaps an archology..., keeping the scale 'small' but 'horrific'.

The PCs have already stopped a sheddim invasion in Egypt, so I don't think I want to use the sheddim as the threat, but what should it be? A new strain of HMHVV? Something that, on touch, cause infection unless you can resist it, making contact with the enemy something to be avoided at all costs? Or perhaps it's a new form of possession.

Watching the sprawling mass of people trying to scale a wall, working as a hive-mind, gave me another idea, involving the Horrors. Perhaps this hive mind is a single entity, pulling everyone together into its will. THe more people it takes, the more 'aware' it is in the physical world. I could see them grasping each other, and taking on a semi-horror shape - a mass formed from parts. This would be a 'see for an instant and its lost' effect, like when the mass rise up, piling on each other, before the tower of people topples forward in a rush of limbs.

Yeah, I want this to be an isolated event, unless the PCs really screw up. Thoughts?