When engaging battle, Tiny must dodge Mad Jack throughout the battle, as mere contact with him will hurt her, and he is bouncing around on towering pillar-like contraptions where the fight takes place on. At some point, Mad Jack will pop out of his box and attack Tiny with fireballs, at which point Tiny must find the switch that can release a stream of electricity that will short out Mad Jack. However, this will only work if the texture of the top of the pillar that Mad Jack is on is the same color as the pillar with the switch.As time goes on, Mad Jack will ditch using fireballs and use lasers instead, which, upon contact with the ground, will send a pillar of energy out and deep fry Tiny if she gets hit by it. She can also get it by the laser when it hasn't hit the ground yet as well. When Mad Jack is nearly defeated, he'll turn himself invisible, making his movements more difficult to track. The same strategy applies to all phases of Tiny's battle with him, so when the stream of electricity is released one more, not only will he short out, but the platform Mad Jack is standing on will lower itself, making Mad Jack fall and break himself, thus ending the battle and Tiny claiming a Boss Key.
- Originally, Mad Jack was going to be called Junk-in-the-Box, and was going to be fought in the same manner as Army Dillo and Dogadon. This was scrapped and Mad Jack's boss fight was re-imagined into what it is today.
- Many fans have regarded Mad Jack as one of the highlights of Donkey Kong 64. This is because of Mad Jack's unique design, the stark contrast with most of the Donkey Kong franchise's lighter tone, and his unsettling laughter, which you can even hear in his boss theme.