Conan the Barbarian (1970) 24-A

"The Song of Red Sonja"

King Ghannif, of Pah-Disha, having sent Red Sonja and a troop of soldiers to Makkalet, has also given Sonja a secret mission. She must make her way into the tallest tower of the city, where the Queen's dowry is kept, and steal a magical Serpent-Tiara. Sonja convinces Conan to help her with promise of sweeter things to come. During the darkest hour of the night, the Cimmerian scales the tower walls and lowers a rope down to Sonja. They soon discover the treasure room, which is filled with jewels, gold a-plenty, and the Serpent-Tiara. In her haste, Sonja forgets to utter the words that will prevent the tiara from coming to life once held. And, it suddenly transforms and grows into a huge reptilian form. Conan and Sonja battle the serpent until it's finally defeated, and make their escape from the Tower. Once on the ground, Sonja quickly mounts her steed, and rides off into the night, leaving Conan alone and with nothing for all his hard work.

Second appearance of Red Sonja.