Rubber Axe

The Rubber Axe is an extremely versatile, invaluable weapon for speedrunners of Super Burn the Rope. It is near useful in most normal contexts since rubber axes only do 1 damage whenever thrown, but the hitbox of Indykirby's throwing animation for this weapon is slightly taller than his idle animation, which lets you clip into any ceiling that you can get close enough to normally. The precision that doing just 1 damage entails also makes it much easier to activates glitches based on particular enemies having certain current HP values. If used in combination with The Dried Blood of the Holy Colossus, it can also reduce max HP values precisely, the only way to pull off several forms of arbitrary code execution.

You unlock it by dying to the Pacifist Colossus Jr. in level 4 with all difficulty levels set to the lowest.

Not to be confused with the Rubber Bullet, an enemy-only projectile exclusive to the police who spawn if you take too long in the Burger King bathroom in Level 62.