Actually, I had a lot of ideas for this one, but they were all ideas well beyond my drawing ability (mostly because they involved people) and time. (I have a super full day today.)
One idea was to draw someone “hiding” while reading under a blanket. I was pretty set on this idea. Another idea was being invisible in a crowd, but given the complexity and number of people I would have to draw, I discarded it pretty quickly. The reading idea stuck for a while, but when I looked at some drawings for inspiration, although I felt I could simplify it enough to be within my skill set, the images I looked at didn’t really say invisible to me, so I sought other inspiration.
Thus, the invisible man. Inspired from this image (link) , I kept my focus on the profile image and left out the face. (However, I did sketch in an outline of the head, worked around it, then erased it. I think that helped get the proportions right.
It lacks the skill, style, and finesse of the original, and boy are there are a lot erasures (I actually worked from a different model first, but it was not a good one starting point), but it gets the job done.