Just like any religion, Buddhism can be distorted and misapplied by the mentally unstable. From the Houston Chronicle:

"Jacky Tran...a vegetarian, thought some meat his son ate caused demons to enter the boy."

When police arrived at Tran's house, "all the windows were open and Buddhist chants were blaring from within. Through an upstairs window, Tran could be seen repeatedly punching down with his fist, prosecutors said."

Tran claimed he was beating the demons out of his son.