I tried something a bit more silly and expansive. Bear with me. I did tell you some would be good, and some would be bad. Inspired in part by this Penny Arcade comic.
In retrospect, this might have worked a lot better in first person, with the invisible friend. Ah, well. Might re-try this later.
Donald’s knees began to buckle under the feelings of new weight, but he couldn’t, for the life of him, understand why. There was nothing on his tiny, child-sized shoulders. His silvery, space-suited hands were empty too.