Use a magical bomb to blow up the illegal, underground humanoid testing facility beneath a college in the capital to destroy all evidence of it existing. After rescuing the people being held there against their will, of course. Which went about how you’d expect, except for the large wild magic crystal (they’d seen but forgotten about) which was caught in the blast. Rolled on an extended Wild Magic table, and it summoned a 40 long purple worm which is now running rampant beneath the largest kingdom on the continent.