These seem pretty infrequent to encounter, and can actually do a bit of damage and mess up up with Broken Bone. Not super dangerous, but enough to perhaps not be trivial in-run. Feels like there's probably something to find here.
I wonder if maybe this only shows up if you don't have Echoing Garage/HQ Alarm active? That gives a pretty small potential window, once you've got a sufficient amount of blood spilled, since the vine thing apparently preventing the guards from noticing seems to be one time only.
Anybody got other thoughts on what the criteria might be for these? I've run into them a total of three times, across two different days, and can't get them to show up at all anymore.
"don't have Echoing Garage/HQ Alarm active" is a reasonable guess. It definitely seems rarer than other encounters but I don't have any specifics why. I've been trying to trigger the huge rat for the last few days but can't get it to show up to confirm/deny that. My old logs don't have specific log of how many turns of effects are active. I'll report back if I can get the rat to show up.
EDIT: Also - I haven't really tried fighting the hounds/guards extensively. I wonder if anything special if you kill enough gatling guards or such? (likely unrelated to the rat)
I've now tried getting to the point of the blood being noticeable by the guards, then killing 20+ guards and some hound drones and letting the alarm wear off, but still no sign of rats, and not much apparent delay in guards finding the blood again.
Huge rat finally showed up. I had the following:
Pep in your Step (7)
Fae Blessing (15)
Muffled Sight (22)
HQ Alarm (22)
Echoing Garage (77)
I killed quite a lot of people today, and ran from a lot more. About the time the gatling gun guards showed up.