Jack had a sudden realisation. This was an Oorkleta! Yes, he remembered The Doctor talking about it...
***FLASHBACK***
Jack lay on a bed in one of the TARDIS' many bedroms. The Doctor and Rose stood by his side. 'What's wrong with me Doc?' Jack mumbled, his voice barley audible. The Doctor couldn't stand seeing his usually flirty, full of life companion so sickly and weak. 'You were attacked. By an Oorkleta. Nasty beings. So so nasty. Bit like trap doors. I've never met a trap door I liked...' Whilst The Doctor rambled on, Rose shot Jack a sympathetic glance. She took his hand and squeezed it. '...And that's why cats don't have opposable thumbs.' The Doctor finished. Anyway, you should make a full and fine recovery Jack, we have the TARDIS on our side. Lucky really; without her you'd most likely be dead.'
'Why me?'
'Huh?'
'Why did it bite me?'
'Oh yeah, the King is a bit grumpy. Can't blame him really, his son ran away. Stole a spaceship. Well, you can blame him because it was his fault. Let's just say the King doesn't support homosexuality and has a lot of rage at the moment. You shouldn't of flirted with him.' Rose looked at The Doctor.
'How old was his son?'
'10'
***END OF FLASHBACK***