Can anybody help identify this anime series with a fighting robot? Two specifics stood out in my mind (which hopefully doesn't indicate my remembering two different series):
The boy who controlled the robot did so by phasing through the rock of a mountain that the robot was in.
The bad/guy witch had a face that would split apart down the centre. I think it revealed a smaller version of the bad guy/witch when it opened.
My guess is going to be late 70's early 80s. It was on US Broadcast TV. So likely it was dubbed into English.