We had one come into the shop (probably 25 years ago) that was like that but full front to back. The car was a Cavalier and there was a recall on heater core replacement. I had done so many that I could do them in 35-40 minutes and the warranty pay was 3 hours. I had a deal with the advisor to give them to me.
I started on this one after throwing the trash far enough out of the passenger floor to try and get it done. I saw movement and focused on a real deal German cockroach.
Anyone who knows me knows I can not be in the same zipcode as a roach.
After the comedy that ensued with me un-assing the car….we told the customer we would not be doing the recall until the car was detailed and critter free.
It never came back