The unofficial cartoon guide to He-Man and the Masters of the Universe features many more abandoned episodes!
"Riddle of the Comet"
When a comet crashes into the planet, He-Man loses his strength. Meanwhile, Beastman's legions storm into the kingdom, and without He-Man's defensive power, Castle Grayskull is sure to fall. Only by unraveling the riddle of the comet...and its strange properties...can He-Man recover his strength and save Grayskull.

* Legally I should say that Larry DiTillio did NOT write this episode. This is merely an example of how the episode title card might have looked.