PRACTICE MODE:
its not hard, just a simple little game manipulation.
in MKtrilogy, 3 and i think MKU3, go to regular kombat with one controller (in the 1st slot) and when you get to pick your character, unplug your controller (carefully...believe me... )and plug it in the 2nd slot. then press start and select a character for PLAYER2. then put it back in slot 1. select your character, and you are free to bash your paralized opponent at will! (im pretty sure you will have to do this every 2 matches, or whatever you have it set for.)