>>16092366OP here
I typically lead with Galvantula@Sash w/ Sticky Web, but always start with M-Gengar if I see a Smeargle, Klefki, Ninjask or any other BP just to use Taunt+ShadowTag to prevent them from setting up; then switch to my Galvy.
It isn't my M-Gengar's only purpose (It's running ShadowBall, SludgeBomb, and FocusBlast for type coverage) but it doesn't hurt to have it as an option. And when it's happened SO MANY FUCKING TIMES I don't see any reason to switch it for another attack. So fuck yourself faggot