I tried to come up with something involving electrolysis and a basilisk, but in the end I decided to go with Faradrake!
Michael Faraday was resonsible for discovering the law of electromagnetic induction, and amongst many things that are named after him (including the unit of capacitance, the Farad) there's the Faraday Cage. A Faraday cage is any metallic surface that distributes electric charge around its outside in such a way that the region enclosed by the surface is shielded from all external electric fields. So, it kind of plays into his defensive aspects, there, and it sort of works well as a way of explaining how Shield Dust works for him.
The -drake part comes from "firedrake", which a synonym for "dragon", of Germanic origin