Even some entirely peaceful gay males feel so-called internalized homophobia towards gay males, including themselves. This is particularly so if their social context is anti-gay and they have not ‘come out’ publicly. For a tiny minority, feelings of shame and guilt might sometimes be assuaged by acting aggressively towards other gay males, which appears to be an example of what Freud termed ‘reaction formation’. Such combined lust-anger emotion appears to be at the basis of the killings by several men (described here), who exhibit sexual sadism. Some serial lust killers were rejected and taunted for being gay. This triggered mixed emotions towards their orientation and combined attraction and hatred towards other gays. The chapter describes several homosexual serial killers, all of whom targeted gay males or young men offering sexual services, often torturing them before killing. Most famous is John Wayne Gacy and most recently convicted is Bruce McArthur.