S1·E33 The Children's Planet

The Scientists of Primus inform Master Sebrian that a deadly gas called the Black Omega has the power to destroy Primus' planetary shield and is located on Omega 4, a frozen planet at the edge of the Tri-Solar Galaxy. Master Sebrian agrees with the Scientists' suggestions to have He-Man destroy the planet with the Black Omega. When He-Man, Spinwit, and Tuskador on Omega 4, he discovers that there are some inhabitants on Omega 4 enslaved by the Mutant Maxus and his two-headed servant named Zark who were exiled there by Skeletor. Maxus and Zark are using the slaves to harvest the Black Omega in order to get on Skeletor's good side.