Here is a page of storyboard panels from the season one He-Man episode "The Dragon Invasion". Even as a kid I was always fascinated by this particular scene in which we see Prince Adam crushed by rock fall during the transformation sequence! Sadly the action happens so fast that none of the characters ever discuss it. It is interesting to see that the storyboards are pretty much the same, albeit with a few changes; He-Man emerges from the rock fall in front of the visage of Castle Grayskull, whereas in the actual episode they simply show the stock footage of Prince Adam transforming into He-Man in front of the castle.
(click on the image to see it at full-size)