Mystery object.
 

Looks like a thimble for counting paper, banknotes etc. Sorry to be boring.
Now I'm off back to the tits n all...

That must be the thumb of an Alien ;-))

It may very well be that but I just searched rubber thimbles and it seems all of them go over and tip of your finger, whereas this object has a hole in the middle of it and not the bottom like a thimble.

Very strange but who knows!

Mystery object
 

TBH I haven't got a clue what it is but, coming from a manufacturing background

The very visible uncleaned flash in the second picture says its a rough finished piece not intended for personal use.

I would suggest its some kind of stop or bumper that has fallen off a piece of furniture been found on the floor and someone has thought that looks important but I don't know what it is, I'll put it somewhere safe.

Not the answer you wanted but the best I can give sorry