This reminds me... (oh no)
I know someone who lives in Florida and they were having a cockroach problem. While staying with them, they told me that if I go in the kitchen, especially at night when they like to come out, and I see one, I was to give them a little squirt of some RAID or whatever it was in the handy can sitting at the ready to do the job. That would be enough to kill them.
Well, I was watching TV and got up and went in the kitchen, turned on the lights and sure enough, there was a cockroach. I grabbed said can and not only did I try to drown the thing, I followed it as it scurried here and there to get away from me.
The next morning, there was a trail of white powder everywhere I followed that cockroach. So yes, it looked like that guy's incision. But worse.