Just my take on the concept, was fun :)

Recipe: MOTUC Skeletor Body
MOTUC Alcala Skeletor Head
Modified MOTUC Keldor Cape
2 MOTUC purple half-swords
MOTUC Horde Crossbow
MOTUC Hordak Boots

Fan Created MOTUC Bio for Horde Apprentice Skeletor (Not canon so he can be whatever you want him to be!)

Real Name: None at this point.

Horribly disfigured by his own failed attack on his brother Randor, the rebellious Keldor sought out the help of Hordak, whom he had been serving as a promising albeit untrustworthy apprentice. Knowing full well that the dying Gar would not honor his pledge of allegiance to the Horde in the long term upon being healed, Hordak fused Keldor with a spirit from Despondos known as Demo-Man. The newly formed being would become known as Skeletor, though the initial effects of the integration left him as little more than a rampaging lunatic at the time. Hordak maintained Skeletor as his apprentice for a short time following the "death" of Keldor but became increasingly frustrated at the realization that his creation was actually harder to control than the former heir to the throne. It would not take long for Skeletor to part ways with the Horde under the new found guidance of Evil Lyn.