She-Ra: Princess of Power
The Magna Beam Transporter was a powerful new invention that Hordak had built at the Fright Zone in Etheria. Its beam could transport any object, no matter how large, to the Valley of the Lost. Hordak's plan was to transport the entire Whispering Woods to the Valley, from which no one had ever returned.
However, it took a long time and very much energy to charge up the Magna Beam Transporter to full power. The ray used the willpower of living beings as its energy source. Therefore, Hordak had set up a machine in the Plunder Room inside the Fright Zone, some levels below the transporter. Rebel sympathizers were put into a transparent cage where their willpower was drained for them to be used by the Magna Beam Transporter. The victims of the Plunder Room then became willing slaves to do the bidding of Horde Generals.