Iron Man #55

Iron Man #55, published by Marvel Comics in early 1973, serves as a landmark entry in comic book history as the first appearance of Thanos, Drax the Destroyer, and Mentor. Written by Jim Starlin, who also provided the pencils, the issue was conceived during a period of creative expansion for Marvel's cosmic line. Starlin aimed to introduce a formidable new antagonist to the cosmic mythos, drawing inspiration from his interest in psychology and the concept of nihilism, which would eventually define the character of Thanos.

The reception of the issue was significant, as it marked the beginning of Starlin's expansive 'Thanos War' saga that would dominate Marvel’s cosmic storytelling for years. While the issue was originally intended to be a one-off story, the immediate impact of the Thanos character led to his rapid integration into the broader Marvel Universe. The artwork, characterized by Starlin's distinct, somewhat surreal style, was instrumental in establishing the high-stakes, psychedelic tone that later became a hallmark of Marvel's space-faring adventures.