Francisia Monahan

Francisia Monahan is an English Spark, who evidently specializes in biological sciences, specifically working with rats.

The Works
Doctor Monahan first appears as a character in the original 2001 version of The Works. She is always depicted in a full face mask with goggles and a mouthpiece.

Dr. Monahan herself is shown — rat in one hand, syringe in the other — with details Mad, Villain, and Spark.

Dr. Monahan’s Rats is another card (with two copies); details are Mad, Giant, and Pests. The two rats are several meters tall.

Finally, Dr. Monahan’s Diabolical Rat Stretching Engine has the detail Machine.It isn't worth any points itself (which is unique), but increases the value of Pest cards for one turn.

The Comic
Distillation of Monahan's venefirous mus elixir is an ingredient required by Gil in the of Tarvek’s inoculation draught.

Eighteen years (for us readers...) after her appearance in The Works, when Gil and Tarvek view the string of recordings made by the Agatha-constructed Wingbot recovered from the lab of Lord Snackleford in the Londinium dome of the Queen's Society, the last of them Doctor Monahan taking possession of the little clank from a fellow British citizen/agent. She evidently is the one who delivered it to the dome filled with disloyal cultists, with Queen Albia never getting any word of the clank's message. When shown the recording, Trelawney Thorpe confirms the Doctor's identity, adding that she has been officially missing for some time, and that she was a friend of Lucrezia's when the latter woman was in school.