We were right to suspect something messed up was going on with the possession mechanic in Mario Odyssey. Cappy has a mind of its own, and if you aren't careful, it can take Mario out of the picture entirely. It's some creepypasta-level stuff.
Twitter user @NichtSascha discovered a peculiar glitch in Odyssey's co-op mode that allows player two to outright kill Mario - leaving only Cappy behind. It's hilarious, yet mildly disturbing. Kotaku's Chris Person recreated the glitch below, and he walks you through the steps needed to create your own existential nightmare:
Unfortunately, there isn't a whole lot you can actually do once Mario is dead. But hey, that's the price of freedom.