According to physicist Hugh Everett, every observation splits the universe into parallel branches. Normally, your memory of the outcome locks you into one branch, like a key keeping a door shut. A new protocol, reality steering, shows you can pick that lock: erase the memory, and the barrier fades, letting you slide into another reality.

But the switch is perfectly invisible. Your new memories will seamlessly match the new branch, so you’d recall events differently and believe they always happened that way. You can never prove you jumped. Still, this turns idle speculation into a serious physics challenge.