The Cheapery St. Heroes: Book Two
Queen Walmar Seburbia is determined to kill six heroes she has foreseen can destroy her. Three are in one universe; three are in another. Her weapon is a powerful Vortex Cannon, and her ammunition is none other than the Muse itself, who goes by the name Zappee. She has weaponized Zappee, filling the Conductor of Dreams with so much energy that Zappee will spawn fatal heart attacks in the heroes once fired at them.
Zappee tries to warn her not to go through with such a dangerous and cruel plan, but the queen isn't listening. She lights the Cannon and fires the Muse into the sky. The Conductor of Dreams splits into two universes, striking six unfortunate chests a moment later.
The rest is just history waiting to be made.