Well, there are many mice in this universe and I cannot tell you what each one would do, but I can report on what the mouse I know has done.
Firstly, it went on a stroll through the local high street, where – by coincidence – there is a high concentration of charity shops.
While there, it thought that in winter there is a bad draft coming from the windows, and maybe this could be fixed somehow. Likewise, it is impractical to have needles here and there, and a little needle holder may be useful. Said mouse also has a liking for blue and red combined together – a bit like you would have in some folky/nordic patterns.
Thus, the mouse proceeded to purchase various material for making and upcycling projects. I was a bit puzzled by what the mouse could do with the things it got. I could not guess, so the mouse had to explain me. I wonder if you can guess? The mouse kindly allowed me to provide some photographical clues.
And this one is not a clue, but simple evidence:
As a little side note, I will inform you that it is customary in our household to blame a phantom mouse for any misfit – mostly involving culinary excesses, like having an ice cream in the night.