Moonstone, also known as Dr. Karla Sofen, is a fictional character in the Marvel universe. She first appeared in Captain America #192, published in 1976. Moonstone is a former psychiatrist who gains her powers after coming into contact with a Kree energy-absorbing device. She has the ability to manipulate and control gravitons, allowing her to fly and generate blasts of concussive force. She is also able to absorb and manipulate forms of energy, including light and kinetic energy. Moonstone is a complex and cunning character, who uses her powers for personal gain and to manipulate those around her. She has been a member of various villainous organizations, including the Masters of Evil and the Thunderbolts, and has often come into conflict with superheroes such as Captain America and the Avengers. Despite her villainous tendencies, Moonstone has also shown moments of redemption and has even worked with the heroes on occasion.