Muting the casters. Classic, and VERY annoying to the caster's player (I should know, I have a DM that created an NPC whose entire raison d'etre is to mute MY caster somehow. In fact, my character in that one game is muted AGAIN...).
After controlling my "have Lucas swoop in to help due to Selene being watching and summoning her" impulses (so, no, it won't happen, relax ;) ), I'd recommend, instead, the aid of someone that's dexterous, quick and able to quickly climb on vertical surfaces such as bookshelves or trees. ;)
And though the being can create silence, it's still a being of potential that fears definition. A dictionary could do it some royal damage. ;)
If I may suggest, maybe Lilly could get her first kill? ;)
