10 Terrible CGI Moments In Modern Doctor Who
4. The Slitheen (Aliens Of London/World War Three)
Series 1's two-part story Aliens of London and World War Three revolves around a takeover of the UK government by the Slitheen, alien creatures who can wear human skin like a suit, allowing them to appear as anyone they like.
While the Slitheen are often depicted with some pretty great practical costumes, there are also several instances where they're portrayed via CGI, and some of these moments look so bad that we're genuinely surprised they were given the thumbs-up.
There are a few shots in World War Three where the Slitheen run down corridors, which, while a poor use of your hard-earned TV licence money, are at least quick. However, the eye-wateringly bad CGI where the Slitheen emerge from their human costumes - see the climax to Aliens of London - is downright embarrassing to watch.
This one is a shame, because again, the practical costumes are really well done, and in fact, so are those moments where the Slitheen zip open their human foreheads. The strength of some of the effects only makes the naff ones stand out more, and visually, these episodes are the very definition of a mixed bag.