I couldn't miss the chance to practice my drawing!
When the player bets the Ichigeki at the Dragon's Neck Coliseum, they will fight Shadow. To activate the bug, the player must choose Gogo to go against him. If Shadow is the first one to attack, and if Gogo chooses the Mimic command, Gogo will mimic Shadow's last attack and attack himself/herself.
This happens because Shadow is classed by the game as a party member. Even if he is an "enemy" for this battle, the game recognizes him as a party member, so Gogo will mimic him as if he were in the party. Gogo's Mimic battle command will mimic the character's action and its target. Shadow attacks Gogo, and Gogo will mimic him by attacking himself/herself.