Non-Physical Interaction

Non-Physical Interaction is the ability to physically interact with objects or creatures that are intangible, incorporeal or otherwise non-physical.

Overview
This ability enables the user to fight an intangible being that normally cannot be affected by physical attacks, such as a ghost. Or to gain access to realms/dimensions that otherwise cannot be physically entered.

It is an extremely rare ability, however, with Saitama so far, being the only known character to possess it. He has been shown to use it in order to enter the Phoenix Space, which he "knocked on" until a hole opened up. Under normal circumstances, this should not be possible since the Phoenix Realm is a spiritual plane that exists only within Phoenix Man's suit. Saitama's use of Non-Physical Interaction appears to be a byproduct of his unparalleled strength, which is said on multiple occasions to defy logic and common sense.