User:SOTO/Forum Archive/The Panopticon/@comment-121.45.54.78-20130925110520/@comment-9435571-20131003141744
From Tardis Wiki, the free Doctor Who reference
Looks like they vaugely referenced a letter from the future being delivered by a guy with big ears and a Northern accent (the license wouldn't allow for anything more). This is a reference to the Ninth Doctor, but I wouldn't count it as an appearance.
