The rivalry between two Marvel monsters first crossed paths in 1962’s Fantastic Four #12 by the legendary team of Stan Lee and Jack Kirby, and they've been butting heads ever since.
The Incredible Hulk’s first issue hit newsstands in May of 1962, a mere six months after monstrous heroes. Previously, super heroes were clean cut and wore bright colors; in contrast, the new Marvel heroes wore dark colors, or had hideous appearances. All of these new characters were born in tragedy or had feet of clay; something that was missing from comics at the time. The Thing and the Hulk were perhaps the best examples of this new trend: brutish looking monsters with personalities, so it was only a matter of time before the two titans clashed.
Over the years, the two have fought so many times that it's hard to believe it started because a bad date. The Thing, wearing a disguise, was out on a date with Alicia Masters, his girlfriend and later wife. Once the Thing’s cover is blown, he is mistaken for the Hulk, which draws the attention of the authorities. Soon after, the Thing is approached (along with the rest of the Fantastic Four) by General “Thunderbolt” Ross for help in bringing in the Hulk. The four agree and are quickly whisked away to the secret gamma base where Bruce Banner, the Hulk’s alter-ego, is working.
The rest of the plot is vintage ’60s Marvel, complete with the requisite Communist spies and a subplot involving the Wrecker, but the key takeaway for fans in this issue was the first throwdown between the Hulk and the Thing. The Thing’s earlier experience being confused for the Hulk added a personal edge to their combat that’s never truly gone away, helping to establish one of the core differences between the characters - the Hulk has never had a problem being what he is, but society won’t allow him to live in peace, while the Thing’s angst comes from his wish to regain the life he had as a human. In this early story, the Hulk’s public profile brings more attention to what the Thing considers his own deformity, meaning that when the two meet, the Thing isn’t just pounding on another monster, but rather the embodiment of his own distance from humanity.
The early Marvel Universe was a breath of fresh air in the 1960s comic book scene, and part of it was due to unconventional characters such as the Thing and the Hulk; these two broke the mold on what a superhero could be and look like, so when it came time for them to meet, it had to be special. And it was, leading to a rivalry that persists to this day, even as both characters have grown, with the Thing accepting himself through found family and the Hulk deciding that if society won’t let him be, he’ll change it into something better - and it all started with a bad date!