Safety Cap

The Safety Cap is an anomalous cap found in some personalized copies of Super Mario 64. It usually takes the appearance of a hard hat as well as some other construction gear. It most commonly makes the player immune to most crushing attacks, excluding a few attacks such as boss fights. However, it has also reportedly given the player a grappling hook on few occasions, and/or hang onto walls for a short period of time.

Safety Cap in the Site
The Safety Cap is usually unlocked in a level commonly known as Safety Cap in the Site, taking the form of a construction site in the sky. The level is usually found through a hidden warp in a sky-related level such as Rainbow Ride, or anomalous sky levels such as The Starry-Night Skies.

It would require the Safety Cap's grappling hook ability to traverse if the grappling hook ability is in the copy, though the level will otherwise have an abundance of crushing objects and enemies such as Thwomps to utilize the Safety Cap's immunity to most forms of crushing.

The level usually has a red coin star similarly to most other secret levels, and a cap switch that is either orange or yellow (not to be confused with the Yellow Cap Switch). However, some reports state there is no cap switch, and instead only a red coin star, and the Safety Cap is either not unlocked or somehow still unlocked.