With Secret Arcade // Dusty Parlor actively on the battlefield, its passive static ability reclassifies all of your nonland permanents and permanent spells as enchantments, turning the entire board into a staging ground for enchantment synergies. When you cast Ghostly Dancers, its entry triggers its own ability to unlock a door or return an enchantment, but because Secret Arcade // Dusty Parlor makes it an enchantment, it simultaneously triggers its own eerie ability to create a 3/1 white Spirit token. That newly created Spirit token also counts as an enchantment thanks to Secret Arcade // Dusty Parlor, which immediately loops back to trigger Ghostly Dancers's eerie ability again without requiring any further mana investment. This creates an unstoppable, mandatory loop of token generation that forces a draw of the game unless a player can interrupt it.