User blog comment:Mckrongs/Monster Hunter Frontier Season Forward 2 and 2011 Anniversary/@comment-3298463-20110909095449/@comment-87.65.143.107-20110913194640

HC = HardCore. A HC monster is an improved version of an usual monster with extra attacks and improved damages (and sometimes with little physical changes, like the "ears" of the HC Tigrex), to make them more difficult to fight and to offer a new challenge to skilled hunters.