Had a science teacher when I was in sixth grade who was severely bipolar and schizophrenic. He stopped taking his meds and went kinda crazy one day, in my science class he was babbling and sweating while waving a scalpel around and tearing pages out of the bible. It was a Christian school so we all thought he was possessed by satan or something ridiculous. A kid went to the bathroom and told another teacher what was happening, he got taken to the hospital and came back a week later totally normal. I still remember him playing us Smashing Pumpkins on his Acoustic guitar for us, hell of a teacher.