- "I've been fighting with one hand tied behind my back."
- ―Captain Marvel
The Photon Inhibitor was a device used by the Kree to control the cosmic powers of Vers. Later, it was destroyed by Captain Marvel once she realized that it was suppressing the true capabilities of her cosmic powers.
After Carol Danvers destroyed the Light-Speed Engine and absorbed the power of the Space Stone, she was taken to Hala by Yon-Rogg and had her memories wiped in order to be turned into a Kree Soldier by the Supreme Intelligence. Being aware of how much power Danvers, now going by the name "Vers" could produce, the Supreme Intelligence placed the photon inhibitor on her to restrain her powers, both as a means to help Vers control her power and to keep her in check should she attempt to rebel against the Kree Empire. Vers was told that the photon inhibitor was the source of her powers. During training, Yon-Rogg would help Vers and try to get her to defeat him without use of her powers, which he also told her came from the photon inhibitor.
Battle at Mar-Vell's Laboratory
During the battle at Mar-Vell's Laboratory, Yon-Rogg subdued Vers with the Magnitron Gauntlets. She was forced to commune with the Supreme Intelligence, which used the photon inhibitor to fully suppress her power, as she had realized that the Kree were the true enemy and had deceived her. However, when Danvers realized the photon inhibitor was not the source of her powers, she managed to produce enough cosmic energy to overload the photon inhibitor, causing it to short-circuit and allowing Danvers to remove it and overpower the Supreme Intelligence using the full extent of her powers.
The photon inhibitor was able to limit the amount of energy Captain Marvel could emit and could even revoke this power entirely. The device could also limit Danvers' physical abilities such as her strength and durability due to the fact that they are directly proportional to how much cosmic energy Danvers produces.