The Doctor looked down at the instrument panels in distress. "What?" he said in his usual befuddled manner.
"Doctor..." Rose said, gesturing over his shoulder.
He turned, to see a petite, stunning blond with large, alluring eyes, wearing a... errr... shiny sparkly white ball dress.
"Jo?" he said in a stunned voice.
But it couldn't be... last time he'd seen Jo, she'd been an old, shriveled, bitter lady who had a million cats and constantly complained about her divorce and her social security.
"Who's Jo?" Rose asked, and he turned to enlighten her. As he stared into his young companion's face, however, he was abruptly overwhelmed by her innocence, her frailty, and the way she wore way too much eye shadow...
"Oi!" the not-Jo called, and he swung back around. His former assistant looked as stunning as she had forty years ago. "Don't you want to know why I'm here?" she asked sweetly, in a voice like small silver bells chiming.
"Uh... sure," the Doctor said, captivated by her youthful charm.
"I'm here, Doctor, because I am secretly a Time Lady!"
"What?!"
Rose looked just as stunned.
"That's right! I was only fifteen when Gallifrey was destroyed, but I was already the smartestest student in the Academy, and besides, everyone loved me because I was so sweet and innocent, and so they fob-watched me into being a human baby and I was placed on Earth in the care of loving parents! But they died, and I was put into an orphanage, where everyone was so mean to me! sniff But I escaped, and joined a traveling circus!"
"But that's completely against canon!" Rose protested.
"Shut up! So anyway, I loved you deeply, Doctor, but you were too old for me! But then after you left, I found this old watch in my attic, and opened it, and now here I am! You're not the last Time Lord! Isn't that great? And you're really much younger and better-looking now, so we can repopulate the Time Lord race! Won't that be fun?"
The Doctor just stood there with his mouth open.
"Don't you agree, dearest?"
"No he doesn't, you !" Rose shrieked. The Doctor stared at this newest development, as his soft, beautiful, heart-breaking companion transformed into a screaming profane harpy with long fingernails. "I was here first!! He's mine!!"
Jo smiled evilly. "My dear, you're just a Canon!Sue. I, however- I am a self-insertion."
"No!" wailed Rose, as Jo transformed into a pimply teenage girl with a laptop. "It can't be!"
"You've lost," the Fanfic Writer hissed as she typed a few sentences.
"Oh, Jo," the Doctor said dreamily. "I'm just so happy I'm not alone!"
"My Time Lady name's not Jo," Not-Jo explained. "It's Sapphire Diamondstar Magenta."
"That's a beautiful name," he said, looking deeply into his beloved's shimmering green eyes. "Didn't you used to have brown eyes, Sapphire Diamondstar Magenta?"
"Where's that poor, ugly human girl who was here?" Sapphire asked, her green eyes filled with concern, like deep, calm pools of algae-covered water.
"Oh, I couldn't let her get between us, Sapphire. I gave the poor girl an easy let-down, then dumped her in Torchwood."
"She won't last the day there," Sapphire said sadly, though her beautiful green emerald eyes glimmered with hidden malice. "Oh well. Now we have to repopulate the species! It's our sacred duty!"
The Doctor's eyes glazed over. "That sounds like fun!" he said, a mind-controlled zombie.
Sapphire pulled out a walkie talkie.
"Mission Accomplished."