This term describes the logos of what are mostly Deathcore, Metalcore, Hardcore, or any other kind of -core bands that are "scratchy", meaning they have lots of extraneous lines that usually represent veins or blood tracks. This usually can make them illegible.
A: Yeah, I like this band Annotations of an Autopsy, but I don't want to buy their scratchy logo shirt.
B: Why not?
A: Cause I know if I get one people will just squint at my shirt until I tell them what it is. And I won't tell them what it is. Waste of time.