Any martial art taught by a self-appointed grandmaster with little or no training in the traditional martial arts. The classes usually consist of lectures about how shitty other styles in the area are compared to the self-appointed grandmaster's style, followed by sparring sessions where the students are encouraged to beat the hell out of each other. Usually, the "dojo" will have a big sign out front that says "tae kwon do - karate" because the dumb shit self-appointed grandmaster doesn't know that Tae Kwon Do and Karate are mutually exclusive systems. Often the self-appointed grandmaster will offer a guaranteed black belt program, provided the student pays an exorbinant fee in advance.
Some Marine Corps boot camp washout guy opened a Mexicali-Ryu dojo down the street. I went in to check it out, and he wanted me to pay $1,500 up front for a guaranteed black belt in one year. I'd rather buy a black-belt on Ebay!