Mutant Dalek embryo

Biology
The creature vaguley resembled a Kaled mutant, although it missed the eye and tentacles. It also looked like a horrible, green human brain. As the creature was barely alive, it didn't have a mind of its own.

History
The Cult of Skaro were the last of the Daleks, so they had to act quick to act quick in order to ensure their races survival. Their first plan was to clone a Dalek embryo, it didn't work and created the mutant. The Cult travelled to Earth in order to perform their next plan, the Final Experiment. The mutant was dumped in the sewers, where The Doctor hooked it up to a strange machine and learned it had an origin from Skaro, which told him that there were Daleks in Manhattan. (DW: Daleks in Manhattan)