It seems that the Ood Sigma, which last appeared in Series 4 during Planet of the Ood, will be returning during one of the specials as it was spotted during filming. The picture to the left, taken by Scooty, clearly shows the Ood, who was played by Paul Kasey. So what would this mean?
Considering pictures of David Tennant filming in his old orange spacesuit, last used during another Ood episode The Satan Pit, have emerged, maybe the whole Beast thing is happening again. It would be interesting to hear some of your theories, feel free to post them below.