Thank you @uggievang
I see. I thought it was 8 heads high. This may require more practice.
More pictures for the perspective assignment. I looked for the horizon line in one and 2-point perspectives.

Here are some rough sketches I made. Perspective sketches and some monster ideas.
I was reminded recently that Star Wars: The High Republic existed and was reminded that this character named Geode existed.
Here he is in the back:

I had an idea that what if Geode is some kind of rock mimic instead of an actual rock? Maybe something like the weeping angels from Doctor Who that only move when you blink or if you can't see them. Then he reveals himself and attacks his enemies. Maybe even Plank from Ed, Edd, and Eddy was a mimic.
