Castle Grayskull Baseball T-Shirt

Castle Grayskull is a fortress located on the fictional planet Eternia. It forms a central location in the Masters of the Universe toy/comic/animation universe and also appears in the 1987 live action adaptation. The concept is credited to Donald F. Glut. The toy set was invented by Roger Sweet. Castle Grayskull was a "major feature of Mattell's line", and was "one of the most famous playsets of all time". In the storyline of the franchise, it is the target of numerous attacks by Skeletor, Hordak and the Snake Men, all of whom believe that the secrets inside will allow them to conquer Eternia and become the titular Masters of the Universe.