The Works cards give some clues. According to the wiki (which is sometimes wildly unreliable but often a good source):
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.
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