Talk:Ultimate Great Spell, World Pandemic!/@comment-32503416-20171229111115/@comment-26684750-20171229115741

They do not lose. This effect of losing your flag lasts for the rest of the game. With it, all cards that you have barring Omni Lords will lose all their text, including size, card type (monster, spell, etc.), and all effects, meaning they will be unusable.