Scott Cohen, Democratic nominee for Lieutenant Governor in Illinois, responded to news that he had attacked an ex-girlfriend with a knife in 2005 by explaining that he had 'roid rage. This is the sort of thing that can happen in a tight six-person race when you don't have a voting system like IRV that is designed for large numbers of candidates. (Not steroid-driven violent assault -- wealthy evil psychos winning office because they spend millions on ads and there are too many candidates for voters to examine them seriously.)
The other top-ticket Democrats -- gubernatorial candidate Pat Quinn and Senate candidate Alex Giannoulias -- have called on him to step down. I don't know exactly what can be done about evil psycho nominees, since they're probably too evil and psycho to respond to ordinary incentives, and they're not in office yet where you could impeach them. But let's hope that Illinois Democrats can figure something out.