Auntie Mehitabel's Natural Causes

Auntie Mehitabel's Natural Causes is a poison with which Zola hit Agatha. Tarvek noticed the stab and to Violetta, who was able to identify it. Gil hadn't previously heard of it, but, it is a slow, subtle poison, really hard to detect, which usually means deadly, unless you know it's there and have the antidote. Which Smoke Knights do, of course.