Here we see a very interesting case of how much an early concept can evolve during development, and finished toy or character.
The first concept-sketch of Skeletor features a far, far more savage version of the now-infamous Lord of Destruction.
He has a big muscular hunched back look, big beard, a strange gemmed little crown-like hat, a morning-star mace, scimitar-like sword, and his trademark Havoc-staff is nowhere to be seen.
In fact, judging from all things, including the armour and overall look, at this stage, he and Beastman where one! The more Savage features would soon be spun off and redeveloped into Skeletors most faithful follower, the savage Beastman.
In the second image, we see a more developed, more or less finished version of Skeletor. Now he's sporting pretty much all of his finished features, his classic Havoc staff, bone armour and head-cloak. The differences to the Skeletor we all know and love, are small. His Havoc Staff was apparently planned to have a feature where the ram-skull could pop off and then be used as a sort of elongated morning star, still attached with a rope to the shaft of the staff. His face seems to have somewhat more skin and dried-out flesh left on it too. And finally, his lower arms are different, having a bony deteriorated, half-rotten appearance, instead of the finalized toys spiky fore-arms.
No doubt the original fore-arms where deemed a bit "too strong" for young children at the time...
Images courtesy of Matt Jozwiak & Mark Taylor