He-Man and the Masters of the Universe (1983)

S2E2 The Energy Beast

Deep within Mount Eternia, an ancient temple is uncovered, leading to an unexpected incident when Orko inadvertently releases The Energy Beast, a formidable electrical demon that once dominated Eternia. He-Man, Man-At-Arms, and Teela embark on a mission to drill into the mountain in search of the Gold Chamber, where the magic crucial to subduing the Energy Beast resides, racing against time. Meanwhile, Skeletor lurks in the shadows, eager to forge a pact with the Energy Beast for his own nefarious purposes.