[X] I should build something! – Alchemy may be able to solve all problems. If stepping on air is possible, breathing under water should not be out of reach. It will take you longer than with any other solution … but the solution will be here to stay. (High DC on preparation time, low DC on time spent under water.)
Another thing about this option is that it could be a future business opportunity in the Triwizard Tournament.
Another thing about this option is that it could be a future business opportunity in the Triwizard Tournament.