In 2259 the Enterprise was ambushed by Gorn warships and forced to hide inside a brown dwarf, where La'an Noonien-Singh's memories of the Gorn helped the crew survive.
While on a supply mission, the Enterprise found a colony attacked by the Gorn and was soon under attack itself. Badly damaged and with crew killed, the ship retreated into the brown dwarf's atmosphere to avoid destruction.
La'an had survived a Gorn attack as a child. Spock used a mind meld to help her recover details of how the Gorn behaved, and Pike used them to set a trap that destroyed the enemy ships. The encounter showed how dangerous the Gorn were long before Starfleet understood them.