We’ve been hearing this in our basement for weeks. Finally trapped it. Any idea what it is? We are in the Denver CO area. http://s36.beta.photobucket.com/user/303me/media/whatisit_zps6eec4741.mp4.html
Wood rat? Pack rat? Some kinda rat.
El chupacabra del diablo. Get out while you can.
Hoop snake
Looks like a woodrat to me. They can make nice pets.
Mkae sure you check out his stash, they are the original pack rats! You might find somethings you have been missing.
It’s Ben!
His friends will come looking for you tonight if you don’t release him real soon.
Anybody lose a chinchilla?
Woodrat as was suggested above. Probably not a good idea to keep it around between fleas, lice and other insect it could be vectoring rabies or other nasties.
I do sort of like the furry tail. I have never liked naked rat/opossum tails:(
Woodrat or Cotton Rat. Get a Merlin Falcon to make short work of it (I’ve seen them do this.) After that you can train the Merlin to hunt sparrows and you can spend the rest of your life feasting on sparrow pie.
Made the topic title just a little bit more specific.
Wut! Isn’t it supposed to be blackbirds?
Don’t get it wet or feed it after midnight!
But the most important rule, the rule you can never forget, no matter how much he cries, no matter how much he begs, never feed him after midnight.
It looks bigger than a pack rat, (except, of course, for my husband) and the link says they only live in North Dakota.
Looks a bit like a marmot to me (they live in alpine-ish country)
That link is from a site devoted to North Dakota wildlife, so it says they live only in western ND. Later it describes the full range, which includes all of the Rocky Mountain area.
I’m pretty sure you have a bushy tailed woodrat. Though at first glance, I wondered if it might be a rogue chinchilla. 
Seeing how the OP cited Denver as home, I’ll say it’s a pika.
Sure looks like it has an external tail to me.