While it's
popular to refer to various commercial nu metal and emo bands (as well as some non-commercial punk bands) as shitcore, shitcore as a genre is actually something quite different. It's a pretty self-deprecating and no-
fi form of underground
music (some of the only real underground
music there is currently) that is deliberately awful and humorously pathetic, often created with (or with the help of) shitty computer programs. There are ACTUALLY subgenres within shitcore, ranging from shitgrind to shit rap even, and the lyrics are often obsessed with coprophilia, gay sex, murder,
suicide, pedophilia, Hitler, and anything else that can be blatantly offensive, stupid, politically incorrect, or all-around gross.
Examples of shitcore include 50 Ways To Kill Me, Suicidal Rap Orgy, Hitlerbuttsecks, and
Kitten Felcher (of which I am a member myself -- good for me, I get an air
biscuit).