Strategically placed near every door, window, sewer pipe, and vent the DM put an Antimagic Field device.
I especially like to imagine a druid coming in through the sewer as a rat and having his robes get soaked in poo when he gets popped out of wild shape.
I put it on my healer because of the downed they get back up with some health part. that is clutch for a healer. Plus I think its funny to make a follower of Shar carry something that casts light.