Aria curses under her breath and mutters something that sounds like a mantra, or something similar. Greenish haze starts to gather around her, with the hint that there's something superimposed over her; another figure standing in the mist precisely where she is. It moves, making a hurling gesture, and with a sound like a sigh and a scream, a piece of that ectoplasmic fog breaks off and streaks across the old tomb towards one of the injured spiders!
(Magic Missile on the most badly wounded, but still alive, spider Aria can see.)