Doctor Who: 10 Villains Who Should Return For Russell T Davies' New Series

10. The Krillitanes

The Krillitanes were a great concept that was wasted in its execution.

Appearing in Series 2's School Reunion, these monsters are - to borrow a phrase from the Eleventh Doctor - "patchwork people", able to cherry-pick physical features and abilities from whichever species they conquer.

But despite all of the tantalising possibilities in that concept - for example, it could've been established that the Krillitanes had stolen regeneration powers after killing a Time Lord - they were depicted as giant bats with almost no interesting abilities.

Great stuff.

It's a real shame, because again, there were so many interesting routes that could've been taken here - so just imagine what a writing wizard like RTD could come up with.

Krillitanes with Weeping Angel and Silence powers? Krillitanes with metallic Cyber-shells? Krillitanes with Pting and Zarbi powers? Okay, maybe not that last one, but you get the point. This is basically a free pass to roll two or three iconic baddies into one, and that potential is definitely worth exploring in the future.