FINALLY, Pony 8. My version of The 8Doctor's regeneration into The 9Doctor: On the last day of his life, while he was by his TARDIS, The 8Doctor was shot by a Sontaran out of vengeance (The Time Lords forbade the Sontarans from participating in The Last Great Time War). He killed the Sontaran who did so instantly with a bottle of coronic acid he had in his pocket. After doing so, he got into his TARDIS & set it to go to 76 Totter's Lane. After he did so, his TARDIS dematerialised. As soon as that happened, he collapsed & regenerated. The TARDIS rematerialised in 76 Totter's Lane. The Doctor regained consciousness & stepped out immediately. He muttered to a local, "They're all gone. I'm the only one left". After trading most of his clothing at an Oxfam in Sheffield, the Doctor dumped his other selves' items in a tip. See 9's TARDIS Index File page for info on The 9Doctor's life pre-"Rose".