Back in 2002 at Pride 21 - Demolition, in Saitama, Japan. American Don Frye faced off against Yoshihiro Takayama the Japanese Giant, In what was supposed to be an MMA fight ended up looking more like an Ice Hockey fight, the two fighters stood in modified hockey stance and went pound for pound for the majoirty of the 6 minute and 10 second fight. The fight ended when the referee stepped in and decided that even though willing to continue, Takayama's face was so bloody, swollen and disfigured that it seemed necessary to call and end to the action.
For any of you who don't know what Pride was, Pride was the Japanese run MMA Promotions company That pretty much dominated the MMA scene for 10 years being broadcast in over 40 countries before finally being sold in 2007 to the Fertitta boys who own Zuffa, which at the time owned the Ultimate Fighting Championship.
Check out a a quick clip that highlights some of the 6 minute fight: