TARDIS coral
From Tardis Wiki, the free Doctor Who reference
The 28 October 2006 Radio Times, in an image of the Torchwood Three headquarters, identified a piece of large coral on Captain Jack Harkness's desk as the beginnings of a TARDIS. John Barrowman, who plays Jack confirmed that "Jack's growing a TARDIS... It's probably been there for 30 years. I suppose in 500 years he'll be able to begin the carving process".
