Shade
Monster Junkie
So we're OK with some kind of "Immunity To Physical Attacks" special ability.
I'm OK with it.
Presumably the "miss chance" you are talking about is the chance-per-round of spotting the Misi's "scintillating form". The original used an Int-check rather than a flat percentage. It seems similar to the way AD&D allowed high-Int creatures to spot invisible opponents, so should we use an ability check or make it a Spot check like you'd do with invisibility?
If we have a check, I'd prefer Spot to an ability check.