After defeating the Jumbo Cock Boss in the Cave of Origin during Generation 1, go back down into the Boss room in the dungeon and encounter the Boss again during random battles. Be cautious as he can also spawn with up to eight other monsters. You will be rewarded with experience, gold, TP, and EP for winning the battle faster. Save the game after each fight so you do not lose your levels, since this battle can go bad very quickly. Also, this is the only room you can find Mandrakes which is required for the Cave of Origins Title located at the Adventurer Hall, the requirement of which is to kill fifteen of each monster in the dungeon.