Kintaro in mortal kombat 2 that fucker has an attack that takes you down to under half health and you can't hurt him to stop it. The last quick draw fighter in Red dead revolver and the Governor is a pest too. Oh and the final boss in gun. In Guilty gear XX number reload the midnight carnival I-no is a bitch to beat too because she has an overly powerful special move but I beat her once in arcade and then never could again. In King of fighters 2003 The final boss is impossible to beat the 1st time through you have to use the aid thing to win.
If you want to neg rep me go right ahead but don't be a pussy and don't post your name if I give neg rep I still do.