"Night and The Doctor" 5 minisodes with River Song! The order is: Bad Night Good Night First Night Last Night Up All Night. Also on this site search "Doctor Who prequel" for other prequels, as well as "Pond Life"
"Albert: They’re a bit like facehuggers aren’t they?// The Doctor: Facehuggers?// Albert: You know, Alien. The horror movie, Alien.// The Doctor: There’s a horror movie called Alien? That’s really offensive. No wonder everyone keeps invading you.