Spoiler alert, if you do now wish to spoil the game, don't open till after you've finished the campaign, especially if you're first going for:
If you are going for things in the recommended order, stop now and come back here after you've finished the campaign and already gotten the above trophy.
*** Spoiler - click to reveal ***You cannot fight Morgan Freeman as a black character, it is recommended that you do the main story campaign going for this trophy first: After you've gotten the trophy above out of the way, go change your race to White by going to the PC Principal at Crunchy's Micro Brew. Then, go to Morgan Freeman's Taco Store and fight him -- to trigger the fight, go behind the counter and hit him 3 times.
Note: you should set Cpmbat difficulty to Casual once you've gotten the trophy above. Morgan puts up a tough fight, but after playing the whole game on Mastermind I beat him on my first try (on Casual). I used Toolshed, Mosquito & Mysterion.