Invincibro is a glitch that allows the Fire Bro that normally remains inside the cave in the Wooded Kingdom to roam the map freely. Because the game does not expect this Fire Bro to be able to leave its designated area, some strange behavior occurs when it is able to access other areas of the map; namely, that it is invincible and cannot be killed by jumping on it.
This invincible Fire Bro has the notable property that it moves slightly upward and backward every time Mario bounces on it, meaning Mario can chain bounces to gain height rapidly. This allows Mario to gain height rapidly if the Fire Bro is positioned against a tall wall, and theoretically allows him to gain infinite height anywhere (although the methods for this are far too difficult for a human to execute consistently).
There are two main methods that can be used to smuggle the Fire Bro out of its cave. One requires the use of two-player mode, while the other requires that World Peace is achieved in the Wooded Kingdom.
Glydon method Edit
This method uses an out-of-bounds clip with Glydon in order to access the cave without activating the scarecrow. In order to use this method, Torkdrift must be defeated in order to attain the state of World Peace within the Wooded Kingdom, which is a prerequisite for Glydon to appear.
- After capturing Glydon at the top of the kingdom, fly to the Iron Road: Halfway Point checkpoint. There is a wall near this checkpoint that Glydon can clip through simply by jumping into it.
- Once Glydon has been clipped through the wall, immediately fly to the right and aim for the cave's interior. This allows Mario to not only bypass the scarecrow that is normally required to enter the cave, but also to take Glydon into it.
- After uncapturing Glydon, capture the Fire Bro and place it on the metal surface near the exit to the cave. If positioned here, it will already possess the invincibility property, since the player is not normally able to capture it to move it around.
- Capture Glydon and walk against the gate guarding the exit to the cave, then jump and immediately press the uncapture button. If done correctly, Mario should clip through the gate as he uncaptures Glydon.
- Activate the scarecrow to open the gate. At this point, the Fire Bro is already invincible, meaning Mario can simply bounce on it a few times to push it backward and out of the cave.
Two-player method Edit
This method requires the use of two-player mode, but it has the advantage that it can be performed prior to achieving World Peace in the Wooded Kingdom.
- Enter the cave as normal using the scarecrow and exit it as the Fire Bro is jumping to the right, so that it stops in its rightmost position. This is done in order to ensure the Fire Bro is as close to the gate as possible.
- Close the gate by retrieving Cappy, then position Mario near the gate with a small gap between, facing toward the gate.
- Perform a Cappy clip by crouching as Mario and shaking Cappy's controller until Cappy clips through the gate, then move Cappy over to touch the Fire Bro and remove its hat.
- Repeat the previous step once the Fire Bro's hat is removed to capture the Fire Bro.
- Position the Fire Bro on the metal surface near the exit to the cave, and uncapture it.
- Again, position Mario near the gate with a small gap, facing toward it. Perform a Cappy clip again using the same steps, and use it to place Cappy on the scarecrow on the other side of the gate.
- After opening the gate, simply bounce on the Fire Bro a few times to push it out of the cave.