A Door Jump is a glitch in the original Metroid game that allowed Samus to jump inside of doors and walls. It is commonly used to find Secret Worlds. It is also used for Sequence Breaking; for example, the Ice Beam can be collected without the Bombs by using this glitch. A variation of the Door Jump is also featured in Super Metroid, where it is most useful for getting to Tourian without killing a single Space Pirate commander. It is also useful for avoiding the encounter with the Big Metroid and the fight with Mother Brain, though Samus still must escape Zebes.[1]