While sitting in the evil chicken lair ranging black dragons i noticed i had a toy mouse in my inventory. Now i know i didnt get it from my bank iam i am pretty sure someone didn't drop it considering the one i am in is empty, so the only thing i suspect is my accumulator. So does anyone know if the accumulator picks them up?

Yes, the Accumulator will pick up toy mouses, as well as various metal items. (Like iron armour), but it is quite rare.