Nice orangeman! Take your pic from a little further away and it looks like it will have some directional markers as well. Might need shadow/light for those.
I would call it man made.
May be plastered, shaped over existing stone, then fire hardened. There are a few spots that look like the plaster has chipped away.
That can only be confirmed by hands on the stone...
Feel it but don't move it from its spot unless you have a record of its exact orientation .... Photo with a compass on one or both lines.