It sounds like you're referring to a well-regarded ROM hack or patch for Ultimate Mortal Kombat 3 (UMK3). One of the most famous and highly praised in the fighting game community is the (sometimes called the "Juggalo Edition" or various balance/fix hacks), but the single most acclaimed "good" version of the UMK3 ROM for emulation is actually the arcade revision 1.2 (often labeled umk3.zip with the correct parent ROM set).