Rat or mouse, indeed. It is raining like crazy, so they look for refuge. I would not use poison, it may kill a cat that would otherwise be welcome help.
I have always gotten them with traps, classic ones or the saw toothed polymer jobs. Peanut butter smeared on the trigger makes it tough for them to pull / run off.
I had one in the garage in LA. The rat was quite fast, so the trap merely hit it in the head. It passed out next to the trap for a while, leaving a large pool of blood and its silhouette. Then it was gone, fading footprints .... until I could smell it a few weeks later ... the dog pointed out it was in the 993. Rear area.
I looked all over the car, jacked it sky high and the dog and I were looking, smelling, using a mirror etc,and finally found it on top of the transmission. Pulled it out with a coat hanger. It had worms coming out of every orifice and was almost liquid, breaking apart in a pile of fur, slime and worms. It stunk so bad, it was really disgusting. I cleaned it as good as I could and even though it was just sitting on top of the aluminum housing, the faint sweet smell of death only was gone after a couple years when I did my full transmission rebuild that included hot tanking the case!
I remember washing my arms up to the pits and washing down the smell and disgust with an 8 oz swig of whiskey.
G