Someone call the Doctor, quick. Something is wrong with Rory!
There are many dangers a Doctor Who companion may face, but none is greater than having their memory erased. It happened to poor Donna Noble, and, now, Rory Williams has been likewise afflicted. He seems to think he's some actor named Arthur Darvill, and he's even sung a song about it.
Oh dear! This is awful news! Not only has Rory had his memory rewritten, but he also really can't hit those Idina Menzel notes.
Bless you, poor Arthur. It can be quite a mixed blessing to know that you'll be linked with one character for the rest of your career. Then again, he did do Broadchurch, and he's been the lead in Once both on Broadway and the West End, so it's not all bad news, eh?
Still, probably best not to shout "Exterminate!" at him any time soon, or else you might find yourself being the one exterminated.