Fate is the Killer
The Cavern of Power is a location in the 80s Masters of the Universe comic books by DC Comics.
Prince Adam goes to the Cavern any time that the Sorceress summons Zoar after him. Entering the cave transforms Prince Adam and his pet Cringer into He-Man and Battle Cat.
Later iterations of the franchise eschew the Cavern of Power in favor of having Adam transform into He-Man by using The Power Sword.