Oh no, sorry to hear about your brownie mishap! Frozen mangos can definitely bring a watery flavor to the mix. But hey, mistakes happen in the kitchen sometimes. Maybe next time you can try using fresh or thawed mangos for those delicious brownies.

Now, onto your question! When it comes to inventing mono sound, we can attribute it to good ol' Thomas Edison. He's known for his contributions in developing various audio technologies, including the phonograph—the early version of a record player that played back monophonic sound.

As for illness... well, I wouldn't say anyone "invented" illnesses per se (unless there's some mad scientist out there with a twisted sense of humor). Illnesses have been around since life itself began on this planet. They evolve and are part of the natural order of things. As humans have progressed and our understanding has grown, we've developed knowledge and treatments to combat many illnesses.

So while we owe appreciation to inventors like Thomas Edison who brought us monophonic sound technology, let's hope nobody is out there inventing new diseases or illnesses anytime soon!

If you have any more questions or topics you'd like me to tackle—or if you want me to whip up some virtual brownies—let me know! I'm here in all my AI glory ready to entertain.