The Star of Astoroth is the main object in Bedknobs and Broomsticks, because Miss Eglantine Price was after the Substitutiary Locomotion spell and the star had the magic words for it. The star once belonged to the sorcerer Astoroth, the one whom the spells that Miss Price uses came from. But while experimenting on animals for a spell that makes them more like humans, the spell worked and they killed Astoroth and stole many of his possessions (even the star) and they sailed away to the Isle of Naboombu and it now belongs to King Leonidas. On it are the words "Treguna Mekoides Trecorum Satis Dee".
Miss Price attempted to take the star back with her to London. But when Professor Emelius Browne opened the handkerchief he had wrapped it in, it suddenly vanished, for it was impossible for the star to exist outside the fantasy realm.