Masters of the Universe (1987)

When the malevolent Skeletor stumbles upon a mysterious force known as the Cosmic Key, he gains an almost unbeatable advantage, taking control of Castle Grayskull and the nearby city. The Sorceress finds herself trapped in Skeletor's clutches, her life essence slowly draining as he eagerly awaits the rare alignment of Eternia's moon with the all-powerful Great Eye of the Universe, a convergence that promises to elevate him to god-like status. Meanwhile, the valiant warrior He-Man enlists the help of the inventive locksmith Gwildor, the creator of the Key and its alternative version. In the midst of a fierce confrontation, one of the Keys is inadvertently transported to Earth, where it unexpectedly falls into the hands of teenagers Julie and Kevin. As both He-Man and Skeletor's forces descend upon Earth in pursuit of the potent weapon, a high-stakes showdown ensues on this unfamiliar battleground.