This is a video of Cody of Cody's Lab (previously: flushing 152 pounds of liquid mercury down a toilet, floating an anvil in liquid mercury, and taste-testing mercury a few times) inhaling helium (low molecular weight, creates high speed of sound) and sulfur hexafluoride (high molecular weight, creates low speed of sound) simultaneously to see (hear) what he sounds like. Do they even each other out? Not really, his tone sort of alternates between high and low, which he attributes to preventing the gases from mixing the best that he could (he references other people who have tried this on Youtube ending with an average tone, which he says is a result of the gases mixing in the lungs due to talking, and, despite it sounding counterintuitive, not breathing the helium first). So, there you have it, science at work. And later? *opens side of overcoat to reveal graduated cylinder and volumetric flask shaped sex toys* Science at play.
Keep going for the video while I walk by the nearest gas station for a little heavy breathing.
Thanks to Jeffrey S, who agrees science is just another word for explained magic.