MechQuest, one of my favorite old flash games thats a prequel to Adventurequest had two universe level weapons at the climax of the game's main storyline. The first destroyed everything in the universe but one ship, and the second, on that ship, reset the universe creating the medieval games that Artix Entertainment is more known for like Adventurequest and Dragonfable. Their games exist in an iirc infinite multiverse and numerous parallel universes are explored in different plotlines, but they never touched on that in MechQuest itself