If supervillains were real...
Lets just say that some supervillains were taken from comicdom and placed into our world. Which ones could the police/army/superpowers effectively take into custody and keep them there?
Say for example the Joker was caught and put in a mental asylum. Would he still be able to escape as easily as he does from Arkham?
If the US government somehow caught Magneto a la the first X-Men movie, would they be able to keep him safely (assuming he was at his movie power level, not how he's depicted in the comics)?
Basically, who could they detain, who would massacre them?