Upon reflection, I realized it was more like a cross between GoM and "Prince of Darkness", a Carpenter flick from the late 80's involving a cylinder of 'liquid evil'. The liquid would drip on someone, possessing them by some collective will and allowing them to spew streams of water to possess others. As a bonus, PoD involved a recurring tachyonic dream-message from the future, warning of impending doom. Now isn't that ood?
So, coincidence? Or is RTD a Carpenter fan?
As for the Doctor Who special itself, the less said, the better. Kind of a waste of an hour, for all the squandered opportunity and missed potential. There were a couple of germs of some good ideas in there, but they were either handled better in "Fires of Pompeii" (which was even referenced in the ep!) or taken care of in the blink of an eye!
An unfettered Doctor could be a great story, but deserves, nay, CRIES OUT FOR, more than a 5-minute character arc! Why even bother when you can have 30 minutes of lovingly shot but wasteful scenes of the Doctor saying he should reallllllllllly be going now.