Chopper was just a normal inanimate pair of scissors until one day when Double Dribble dropped his orb on the desk and it rolled onto the pair of scissors. While Double Dribble left and didn't notice, Chopper had been "born". Unfortunately, the orb had not been in contact with the scissors for it's full effect. But why didn't the orb effect the desk as well?

Strength

Can cut.
Small.

Strength Source
Double Dribble's orb.