Think I might switch this with (((Jittery Gnome))) or (((Obsessive Artificer))).

Oh, neat. I like the idea of built in work arounds for certain types of magic. A pity that it works best with Shroud--a keyword mechanic that's unlikely to return.

Still, I could easily see this mechanic on a creature with hexproof that has a 'vulnerability' to enchantments, for example. Or maybe on a creature with protection from white?

Ooh, what about one that had hexproof for instants and reverse hexproof for sorceries (or vice versa)?

Possibly an interesting thing, but I won't put it in common.

Oh, I wasn't suggesting it for this card, I was just riffing off jmg's idea.