After a brief test run in the last 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, stylized as Marvel 2-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, 2-in-One continued even after the Fantastic Four's return in August 2018, but officially ended in January 2019.
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).
- Team-Up Series: Almost always involving The Thing and another character. The 2018 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.
- American Eagle: American Eagle is a Navajo superhero whose costumes are based on the color scheme of the American flag. His original outfit featured an eagle feather war bonnet and he has a motorcycle helmet shaped like an eagle's head.
- 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.
- An Ass-Kicking Christmas: The first team-up with Ghost Rider takes place on Christmas Eve and is titled "Silent Night… Deadly Night!" It begins with Johnny Blaze coming across what appears to be the Three Wise Men and seemingly ending up in Bethlehem, while the Thing is busy celebrating Christmas with his loved ones (except Reed, who's being a workaholic even at this time of year). Eventually, the Thing ends up at the same place as Ghost Rider and helps him solve this mystery. It turns out this was just a scheme by Miracle Man (a minor Fantastic Four villain), who brainwashed the inhabitants of an Indian reservation into believing they were part of the Nativity Story and created a child totally immaculately to show that he was absolute and could obtain godhood.
- 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.
- Brains Evil, Brawn Good: Annual #5 has the Hulk and the Thing foil a complicated, centuries-long plan by Pluto to destroy the universe, which even took out the Stranger, by smashing the ground underneath him really hard so he falls into his machine.
- The Bus Came Back: An early issue had the Guardians of the Galaxy make their first appearance since their debut in Marvel Super-Heroes back in the 60s.
- Captain Ersatz: Wundarr is a barely even veiled knockoff of Superman. DC were not very happy about this one.
- Cassandra Truth: Tarin, a human woman who had been enslaved by the Badoon, approaches the resistance on Earth to tell them about the heroes she's brought to the 31st century, but what with the whole "worked for the Badoon" thing, they're extremely reluctant to believe her, until another one of their number rushes in to tell them it's true.
- Character Shilling: Marvel Feature #12 is drawn by Jim Starlin. By mysterious coincidence, it features characters talking up how powerful and dangerous Thanos is a lot, when the most he's doing is... sitting on a chair.
- Crossing the Desert: At the end of Marvel Feature #11, the Thing is stranded in the desert and must walk back home. The following issue begins with him still stranded in the desert and coming across Iron Man, who ignores the F4 member because he's too busy hunting Thanos. After a fight with the Blood Brothers, the Thing asks Ol' Shellhead if he can help reach New York, but the fight drained the majority of Iron Man's power, preventing him from helping Ben. The first issue of Marvel Two-in-One has the Thing finally reach a bus stop, but he decides to pay a visit to Man-Thing in order to complain about ripping off his name before going back to New York.
- Crossover: Beyond its nature as a Team-Up Series featuring many Marvel characters, it also featured appearances from Doc Savage and Rom, who appeared in comics published by Marvel at the time.
- 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.
- Improvised Weapon: In issue #5, as Ben, Captain America and Sharon Carter are running from the Badoon, Ben spies a nearby futuristic car. Cap questions whether he could even drive it, but Ben reveals he wasn't planning on driving it, as he hurls it at the troops.
- Internal Homage: In Marvel Feature #11, while having an argument with Mister Fantastic, the Thing strikes the same pose he did on the cover of Fantastic Four #51.
- Let's You and Him Fight: A common way for Ben to interact with other heroes:
- Marvel Feature #11 has him being forced to fight the Hulk because of a contest between Kurrgo (an obscure FF villain) and the Leader.
- The first issue to feature Thor has the God of Thunder being mind-controlled by the Puppet Master to fight the Fantastic Four. He managed to knock out Ben’s teammates before coming back to his senses. Later, when Thor ends up being mind-controlled again, he fights the Thing, who had more luck than the rest of the F4 thanks to Wundarr foiling the Puppet Master's plan.
- Made a Slave: Tarin, a woman on Badoon occupied Earth in the 31st century. Since this was the 70s, she doesn't specify what kind of slave, but her skimpy outfit makes clear it's not "kitchen scullion".
- 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.
- Mind Probe: In issue #5, Captain America is subject to the Badoon mind probe, which painfully scans his memories and forces Cap to recount the events of the previous issue, for anyone who came in late.
- Mundane Made Awesome: An issue written by Chris Claremont has his usual melodramatic narration used for... Ben getting mobbed by adoring children.
- Faced with the Monster of the Badoon, Ben tries hitting it with his hardest punch, and is alarmed when it doesn't so much as wobble.
- Daredevil tries to steal the Fantasticar without asking the F4's permission because he was in a hurry. He is then caught by the Thing and tries to make the latter release him by kicking him in the solar plexus. However, this does nothing to Ben, forcing Daredevil to explain why he needed the Fantasticar before Ben agrees to help him.
- Omnicidal Maniac: Annual #5 had Pluto attempting to use a nether-hole to destroy the entire universe so the other Olympian Gods would go with it.
- Recognition Failure: When he enters the Baxter Building to retrieve his cane, Daredevil comes across the janitor, who asks him if he's Captain America.
- Rodents of Unusual Size: The climax of #6 has the Thing and Doctor Strange fight a giant rat.
- Screw This, I'm Outta Here: Spider-Man had this briefly in the second Annual issue (which wraps up the 1st storyline). Spider-Man teams up with the Thing to fly a craft to Thanos' warship to rescue The Avengers. During the battle, Spidey realized he was vastly outclassed by Thanos (the fact that he had seen him trash the Thing didn't help). However, as he flees through the ship, he realizes if he doesn't stop Thanos, Earth will be the next target and escaping won't matter. He returns and rescues the Avengers by bravely throwing his body into the machine that held them in stasis. The impact destroys the machine, freeing them (he's knocked unconscious, but recovers).
- The ship of the Guardians of the Galaxy, the Captain America, looks like an upside down Enterprise.
- During his first team-up with Doctor Strange, the Thing ends up fighting a giant rat and calls it "Mickey".
- 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).
- The War Has Just Begun: With help from Ben, Captain America and Sharon Carter, the Guardians of the Galaxy manage to overthrow the Badoon occupation of New York. Now the Guardians just have to defeat all the Badoon on the rest of the planet, and all the other human planets they've taken over as well, while Ben, Steve and Sharon head back to their own time.
- Time Travel: This is how the Thing gets to interact with heroes who are from different time periods:
- The first team-up with Captain America has the Thing accidentally activate Doctor Doom's time machine, which causes the arrival in the present of Tarin, a woman from the year 3014. She reveals that there's a Badoon invasion happening in her time period, so the Thing, Cap, and Sharon Carter decide to come to the future with her to help against said invasion. The story continues in the following issue, where they meet the original Guardians of the Galaxy.
- Issue #21 has Ben and Johnny accidentally time-travelling to 1936, allowing them to meet Doc Savage.
- Tyop on the Cover: The first issue infamously has a typo which transformed the title to Marvel Two On One in the corner. To makes things worse, the two characters appearing in that issue were the Thing and Man-Thing.
- Wowing Cthulhu: In Annual #7, an alien calling himself the Champion of the Universe challenges every superhero 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 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.
- Blah, Blah, Blah: In issue #11, Mister Fantastic is explaining something to the Thing, but all the latter hears is:—so the new question was: is the inhabitation mutualistic, commensalistic or parasitic? Perhaps the blah and the whatever with the thingabob and the whatsacallit beep bop sciencey science I love science and uh, Ben? Ben? Did you hear any of that?