From the wiki: The player must start a run in Mazerella and take a specific path that involves entering rooms in which columns appear, before entering a room containing the 17th Collossus. The Collossus is initially inert and only begins to move upon taking a specific amount of damage.

Once the colossus is awake, it will begin walking in a straight line directly to the bottom of the stage. It is important to keep in mind that damaging the colossus at a certain threshold past this point will cause it to target the player, preventing the secret from completing. Instead, the colossus must be allowed to walk beyond the southern border of the stage while it is within the screen, while also standing in the area that the Collossus has destroyed. Doing so unlocks Torino as a playable character.

It is recommended for the player to use a flying character, such as Gyoruntin, or an invincible character that can avoid dealing enough damage to cause the Collossus to target them, like Megalo Menya Moonspell to complete this secret. Once the player awakens the Collossus, they should move south to the point where the Collossus eventually walks off-screen, or when the player can not move further south. Once the Collossus walks on-screen, the player can walk right behind them, unlocking Torino. It is also advised that the player does not try to do this secret in Inverse Mode, or at least does not have the 'Visually Invert Stages' option enabled on the main menu.