Griffin I appeared in Strange Tales. The Griffin's power came from a mutagenic serum that mutated him further every time he pushed the limited of his superhuman abilities. He continued to grow more bestial and add to his special powers until the serum mutated away his intelligence. He was kept under Namor's care, who was using him as a personal flying steed. Recently, in New Avengers, he reappeared with his sentience apparently restored.