Martha (Deadly Denizens)

Martha is a goodhearted woman who suffers from nightmares predicting the arrival of the tarrasque and always tries to help people prepare. In truth, she is a were-tarrasque, although she does not know what triggers her transformation (which are thankfully rare and brief). Killing her results in an instant transformation into tarrasque form, possibly for good. (Inspiration: The Book of the Tarrasque.)