Dr. Joopy's suit battle
Douglas' Suit is a secret boss in High On Life. If the player kills Douglas's alias, Dr. Joopy, with Gus before the boss fight, this secret boss will replace Douglas.
The way to unlock the secret boss is to have Gus equipped during any of the puzzle sequences. As long as you have Gus equipped during the final puzzle, you will be able to shoot Douglas and mortally wound him. Gus will notice that Dr. Joopy will frequently mix up his kids' names and grow suspicious of him. Upon reaching the final puzzle, You will be prompted to shoot the cephalopod alien with Gus after a bit of dialogue. Upon shooting him, the now mortally wounded Douglas will return to his suit in the boss arena but will die upon reaching it. However, Douglas's suit will enter an Autopilot mode and attack the Bounty Hunter, taking Douglas's place as the boss.