How to get bug:

-Have Minecraft Dungeons on Switch

-Get into a game (it doesn't matter where you are)

-Put the console in sleep mode. Make sure you were using a wireless controller.

-Turn the game back on with NO controllers connected (detach Joy-Cons, open the game via touch screen).

-Bug complete! This softlocks the game, even if you reconnect a controller. You can do nothing except restart your game.