Doctor Who Series 10: 12 Easter Eggs & References You Might've Missed In "Knock Knock'

The mysterious disappearances in Knock Knock are all down to some creepy alien woodlice that have the ability to suck you into the wall, swarm all over you and eat you whole or, for some reason, also turn you into a wooden person.

This isn't the first time the Doctor has faced alien woodlice. Back in 1984's Frontios, the Fifth Doctor and friends land on a human colony world where people are being dragged underground to their deaths. It turns out the culprits are the Tractators, human-sized insectoid creatures.

Likewise, the Doctor has met several wood women before. He had a flirtatious relationship with Jabe, one of the Forest of Cheem, in 2005's The End of the World, and then met the Wooden King and Queen in 2011's The Doctor, The Widow and the Wardrobe.