Cyber middle finger
Fell Buttspoon is not a person. Rather, it is a running gag among runners of Seattle.
It’s something of a ballsy move, but if you feel like leaving an indication that something was hacked, or that a lock was opened by an unauthorized user, instead of using an existing ID, or something banal that might not be noticed, you can leave something outlandish and obviously false.
Usually, you don’t want your hack/infiltration to be noticed. But some people like to antagonize their targets for whatever reason.
No one is sure who thought up Fell Buttspoon, but if you overhear runners talking about Buttspooning a target, it’s probably not what you think.