If I let myself, I become upset and a bit terrified by smooth hard structures. A good example is the most perfect sphere in the world, seen [here][1]. It's a polished sphere of solid silicon-28.

The metal cylinder held by the host later in the video also creeps me out.

A sphere of smooth concrete, granite, marble, or some other hard substance is the worst.

What's the best prefix for my -phobia?

(I think the reason for this phobia is that I slipped and whacked the back of my head against a smooth concrete surface when I was very young.)

  [1]: https://www.youtube.com/watch?v=ZMByI4s-D-Y