Please DO NOT add to this discussion.
At the beginning of "Time and the Rani" the Sixth Doctor regenerated, seemingly with no explanation. However, if you pay attention to the previous episodes, and using information gained from the new series, the reason for the Doctor's regeneration becomes obvious. Two episodes previously, in "Terror of the Vervoids", the character of Melanie Bush is introduced. Mel is someone who knows the Doctor in his future, who has met earlier in his own timeline. Sound familiar? Melanie Bush is clearly River Song. At the end of "The Ultimate Foe" Mel is persuading the Doctor to exercise and drink carrot juice. The Doctor is a nearly immortal Timelord, who gets more than enough exercise with all the running he has to do. Why would Mel want him to exercise. Clearly, all she is really interested in is getting him to drink the carrot juice. Think about it, one episode ends with the Doctor being forced to drink something against his will, and the next episode begins with the Doctor regenerating. The carrot juice was obviously poisoned. Remember what Dr. Song said, she killed a great man, a hero to many. She clearly killed the Sixth Doctor. With the Rani disguising herself as Mel, and the Doctor believing Mel to be the Rani, the Seventh Doctor was probably so confused that he believed that it was the Rani who murdered him, rather than Melanie "River Song" Bush.69.251.176.120 02:59, April 26, 2011 (UTC)
OMG, you could be onto something...River did say she was a screamer, and Mel spent about half her episodes screaming... 187.78.68.129 14:22, April 26, 2011 (UTC)
One slight problem: The 6th Doctor was not a hero to many; to most people, he was an obnoxious twit who nearly caused the death of a beloved show. (Sure, he became a hero to many decades later through the BFAs, but that's because he wasn't being written by Pip & Jane Baker anymore, and because we couldn't see his jacket. It certainly wasn't true at the time of his death.)
And one major problem: River Song is smooth and sexy and fun, while Melanie Bush is... Melanie Bush. Maybe this just proves she's a Time Lord, and regenerated at some point, since we all know that can easily happen to Time Lords... but still, the Doctor may have regenerated into Colin Baker, but he never went _that_ far.
But still, I'm sticking with my own theory: the reason the Doctor died from a little bump on his head is that he had no will to go on living, knowing that he'd have to deal with Mel--and, worse, with that horrible jacket--if he did so. And who can blame him? --99.33.26.0 07:45, May 5, 2011 (UTC)
More and more evidence is supporting my theory. Come on, Mel Bush and Mel Pond are clearly the same person.68.33.231.113 06:34, June 12, 2011 (UTC)
As has been said elsewhere on this site, Mel Bush was a doughnut, River Song is not a doughnut, therefore River Song is not Mel Bush. The above theory is, at best, utter drivel. --89.242.69.47 06:48, June 12, 2011 (UTC)
Now that we know that she can regenerate, it doesn't matter that River isn't a doughnut. Just compare the sixth Doctor to the rest of them. No other Doctor is nearly as annoying as him, but regeneration changes your personality, so Bonnie Lanford presumably regenerated into Alex Kingston at some point.68.33.231.113 15:49, June 12, 2011 (UTC)
It's still utter drivel. --2.101.59.209 17:23, June 12, 2011 (UTC)