*Russian Sergei Kravinoff was a Safari guide in Africa until hunting became illegal. It was in Africa that he fell in love with Dr. Mariah Crawford, who developed a miracle serum made from native plants. When Sergei was attacked by wild animals, Mariah used the serum to save his life - but at the unexpected cost of becoming animal-like. Spider-Man became Kraven's enemy when he tried to prevent the beastly man from taking Mariah back to Africa, against her will. *Source: Back of Card