A play on the word "Sainthood," this is when a person who appears to be extremely kind, generous...just good in general, actually turns out to be anything but. Tends to induce trust issues in people when they find out.
"Mother Teresa was declared a saint, despite the fact that she was a child trafficker, and her healthcare was downright awful. She also refused to let people die in peace -- refusing painkillers and even waterboarding (baptizing) them -- saying that 'Suffering brings you closer to god.' What a great woman, right? Sainthood doesn't fit her at all; more like 'Satanhood.'"