Happy Flowers was a band from the US that played from the mid-eighties into the early nineties, and played music that sometimes is very, very disturbing. It's usually almost tuneless noise (on electric guitar and bass) with wailing and screaming. Just going to their homepage will let you hear a typical sample from a song I bet is called "Mom".

They also have a myspace page, where you can download four tracks. The tracks you can download aren't as bad as I want to watch cartoons (you'll need some sort of RealAudio playing player to listen to this), which I find really unsettling.

Apparently the music of Happy Flowers is also sometimes used by some soldiers posted in Iraq for psychological warfare purposes, linky.