Winifred Gillyflower

Winifred Gillyflower was a mad old woman who blamed her husband for her daughter blindess when in truth it was Winifred who experimented on Ada. Winifred allowed a red leech she nicknamed Mister Sweet to live on her chest, feeding on the nectar of Winifred herself. She planned to poison the air with Mister Sweet's own poison. The Eleventh Doctor, Clara, Madame Vastra and Jenny Flint successfully stopped this plot, and Strax killed her. (TV: The Crimson Horror)