After a brief test run in two issues of Marvel Feature, Two-in-One officially replaced the former in January 1974. Capitalizing on Thing's popularity with younger readers, Two-in-One was generally used to introduce new characters, or reintroduce obscure ones. His gruff, abrasive personality also led to many entertaining matchups, providing further fodder for the series as it ran.
Because of its anthology comic nature, Marvel Two-in-One has been written and drawn by many creators over the years, including (but not limited to) the likes of Jack Kirby, Chris Claremont, Steve Gerber, Bill Mantlo, John Byrne, Frank Miller, and George Pérez.
Marvel Two-in-One ultimately lasted a hundred issues and seven annuals, getting replaced by a Thing solo series in 1983, which in turn ran for three years.
In 2017, it was announced that a revival of Two-in-One would be written by Chip Zdarsky, as part of the Marvel Legacy initiative. The main thrust of this new series pairs Thing with the Human Torch (and later, Doctor Doom's Iron Man) as they search for the rest of their missing F4 family through the vast multiverse. Despite its initial premise, Two-in-One continued even after the Fantastic Four's return in August 2018, but officially ended in December 2018.
Compare with Marvel Team-Up, which involved Spider-Man pairing up with another hero (and yes, Ben and Spidey occasionally joined up in each other's books, even having a crossover that debuted in MTIO #17 and ended in MTU #47).
Two-in-One contains examples of:
- Anthology: The original series largely had this quality, with stories generally standing on their own as individual adventures. The revival, however, averts this, opting for connected story arcs.
- The Bad Guy Wins: Annual #7 featured the alien Champion of the Universe defeating all of the heroes that trained to fight him, but he ended up sparing the Earth because he found The Thing to be a Worthy Opponent.
- Ghost Town: Lawless, Arizona in issue #14. This one had a literal ghost, a hanged outlaw that the Thing and Daimon Hellstrom AKA the Son of Satan battled.
- Meet Your Early Installment Weirdness: In the earliest issues of Fantastic Four, The Thing was lumpy and scaly, entirely humorless, and spoke in a slightly elevated tone reminiscent of Frankenstein's monster. In the fiftieth issue of Marvel Two-in-One, the rocky, Noo Yawky, Deadpan Snarker we all know and love traveled back in time to meet his earlier self. He also undid the earlier Thing's transformation, but this turned out to be a separate timeline so he was unaffected in the present. The consequences of Ben doing this, especially regarding the outcome of The Coming of Galactus, were explored in the hundredth issue.
- Shout-Out: The cover of issue #91 features the silhouette of what appears to be Batman, giving the impression that it's a crossover with the Distinguished Competition's iconic vigilante. Of course, that's not the case and the silhouette actually belongs to the antagonist of the issue, the Sphinx (a Nova villain).
- Team-Up Series: Almost always involving The Thing and another character. The 2017 revival usually partners him up with Human Torch, though certain issues have swapped the latter out with Doctor Doom (as Iron Man) and Mister Fantastic.
- Wowing Cthulhu: In Annual #7 an alien calling himself the Champion of the Universe challenges every super on Earth to a series of one-on-one Boxing matches, with the fate of Earth at stake. He defeats every one (some by disqualification, such as the Incredible Hulk tearing his gloves off and starting a No-Holds-Barred Beatdown on the Champion). Finally, it is up to the Thing, who impresses the Champion because he just won't quit. Even after being knocked out, he gets back up for more. Eventually, when the Thing is a battered bloody mess and the Champion isn't even winded, the Champion suddenly throws in the towel saying that the Thing won: while the Champion could beat the Thing, he could never defeat him. And thus the Earth is saved.