The Mana Waste

From the description: A chaotic and magical place transformed by the power unleashed by a wizard's experiments. Your party must take the Seed of Reconstruction to the heart of the magical rupture to repair it and stop the waste from spreading. The Mana Waste is system agnostic, one-page dungeon ready for any ruleset. A hex crawl and a dungeon, plus new creatures make for a fun one-shot anytime.