Blow up? No, not quite... [Pausing for a moment, as PM can't remember when she said it blew up. Maybe Terezi misinterpreted something overheard...? It's a difficult recollection for her, so her words are kind of strained, but she pulls it out anyway.] The Sovereign Slayer used the Black Queen's Ring to kill everyone in Prospit and set the entire planet on fire. Then he cut the moon's chain and let it crash into the Battlefield...