Well, I gotta figure that stunning would be the easiest, but if we want to talk the inconvenience of Visser Three (which probably wasn't a huge deal to him anyway), I gotta go with some of the previous statements and say bio-stasis. I mean, we saw it in 16; it still takes a second or two for someone who was in bio-stasis to snap out of it, but no long term side effects. Plus, even dracons on low power still singe and burn a bit, making that kind of stunning something the Visser would surely get annoyed with. Anywho, that's just my two cents.