Shadow Milk Cookie channels the energy of his other-realm to begin a grand spectacle of Deceit. Inflicts Puppet Show at the enemy with the lowest Max HP (targets Cookies first excluding Safeguarded Cookies). The opponent's Shadow Milk Cookie cannot become a target unless no other possible targets are left. Puppet Show can also be applied to Cookies who are resistant to interrupting effects. For the duration of Puppet Show, both the target and the nearby enemies sustain periodic damage. The effect ends with a Grand Finale. Grand Finale deals damage to all enemies, deals damage proportional to Puppet Show's target, and applies Taint on them. If the target is defeated before the end of Puppet Show's duration, a Soul Phantom will appear in their place. A portion of the damage sustained by the Soul Phantom until the end of Puppet Show will be inflicted as Grand Finale's extra damage.

If Shadow Milk Cookie is defeated, he will assume his Shadow Form. He will summon his Puppet to fool the enemies and retreat to the other-realm where he will gain Power of Deceit. The Shadow Form effect will last until the Puppet is defeated.

At the beginning of the battle, Shadow Milk Cookie will summon the Eye of Truth. Depending on the number of debuffs received by the team, including Shadow Milk Cookie himself, the Eye of Truth will gain stacks of Truth. More stacks of Truth will be gained whenever Shadow Milk Cookie uses his skill. At a certain number of stacks, the Eye of Truth will remove all debuffs from the team and increase the amount of damage dealt by Shadow Milk Cookie at the expense of a greater amount of damage received.

When Shadow Milk Cookie gains Power of Deceit, the Eye of Truth will transform into the Eye of Deceit, periodically gaining new stacks of Truth. At a certain number of stacks, it will emit a Tenet of Deceit, dealing damage and resetting the duration of Taint on the target (damage proportional to Max HP is capped at 300,000).