The phrase By the power of Grayskull comes from the Masters of the Universe franchise, debuting in the 1983 animated series He-Man and the Masters of the Universe. It is the invocation Prince Adam uses to transform into the hero He-Man by holding his magic sword aloft. The line became one of the most quoted catchphrases of 1980s animation and lives on in memes, parody videos and nostalgia edits, where it signals an instant, over-the-top power boost or heroic reveal.