Probably a known bug, but I've only seen it the past couple of weeks. A trap goes off on a chest, big explosion graphic, but no damage, no blind, no Earth-shattering kaboom. Just, one rollerrat. That's all. Usually orange to me. Kinda cute. Doesn't attack me. Seems to accept Pet commands, but just ignores them. Won't even follow me. I think I understand the thought, but I'm pretty sure this isn't the intended result.
Sathar, 37 Neut NT RK-1