...is an opossum. Ben saw it eating the cats' food out of their dish last night. It appears to be a juvenile, possibly the same one we saw trying to break in the front window a month or two ago. It's taken up residence behind or under the oven. I called animal control; they suggested I take it up with maintenance. I called my landlord* at about 10 this morning; the lady there said the maintenance guy would call me. it's now 2, and I haven't heard from him.
So. I also called a wildlife rehabilitator and googled "possum in house" and I am going to try to trap and release it tonight. (Possums are nocturnal. They also eat cockroaches. I hope he's snacking away while he's visiting. Our building is
old.) Most possums are transients and will move on after a few days, but this one might be stuck, depending on how he got in. Possums do not usually have rabies. (This is good to know. We snagged the tiny human and decamped to my parents' house last night b/c the idea of a wild possibly sick animal roaming around the apartment was not appealing. The cats were left in charge and seemed to have regulated adequately.)
The trap suggested by the possum website is a kitchen trashcan tilted at a 45 degree angle, atop a stack of books or something, baited with catfood or ripe fruit. The possum climbs in and can't get out. If this works, I'll then release it a few blocks away and hope it does ok. I don't want to kill it, I just don't want it living with us.
*programmed into my phone as "Slumlords."
ETA: possibly a picture of the possum. Definitely a picture of A possum, and also our cat Buckley, who is very interested in marsupial B&Es.

ETA2: I don't know why that picture is huge and sideways.
ETA3: Should be fixed