I guess one of the prompts going around today is for your wildest idea for a Doctor Who relaunch, which I ought not to play because the last time I did they took me seriously.
Have they ever had Doctor Who regenerate into his own companion? Like, the Doctor dies, he regenerates young and plucky, and then gets into a situation where he loses his TARDIS and ends up having to travel with an earlier version of himself that doesn't know that his new companion is a future him?