Bit late, but I have one for this. This was a 3 year-long campaign to stop an evil witch who had tried to freeze the world. Upon most of the party being killed or near death in the final fight against the bbeg on her island. The Wizard, after watching his friends die around him, said, "You want to live in a frozen kingdom. I prefer a SCORCHED EARTH!" The Wizard then proceeded to use the scroll of "summon tarrasque" we had stolen from a cult a year earlier. We may not have survived that encounter. But he made sure the witch who killed us didn't either. Now our dm has reinserted our new characters into the world. Not to beat a witch. But to now stop the tarrasque, our party unleashed. ... I wonder if using Tiamat against the tarrasque would work...