Delphi (Beautiful Chaos)

Madam Delphi was a Mandragora who wanted to take over the human race

she wanted the human race to save the Mandragora from dying forever

she also wanted revenge on the Doctor and would use her power over earth to gain that revenge

Madam Delphi had the power to take over many people including Wilf Motts friend Netty

The Doctor Wilf and Donna then began battling Madam delphi who was about to launch her plan to distroy the earth

this was foiled by The Doctor who used Nettys mind to trick Madam Delphi sending her and the other Mandragora back into space