Omitted material: Marvel Two-in-One 21

Left out of Essential Marvel Two-in-One volume 1 is issue #21, which features a team-up with the licensed character Doc Savage (previously seen in Giant-Size Spider-Man #3 so I won't describe him again here). The issue is written by Bill Mantlo and drawn by Ron Wilson.

With Doc Savage based in the 1930s and the Thing in the 1970s it takes some ingenuity to bring them together. The first half of the issue is a split narrative as Doc Savage and his aides Renny and Monk are visited by a woman frightened by her scientist husband's plans to tap the power of the stars to become immortal, with the equipment draining the city's energy. In the present day the couple's daughter comes to the Thing and the Human Torch with a similar tale of how her brother is trying to recreate his father's experiments with similar consequences. In both eras the heroes rush to the site, although only in the present day do they take the woman with them, where their flying craft is accidentally hit by the cannon's beam, deflecting the energy back. It creates a temporal anomaly that fuses father and son together into one being called Blacksun and brings all the heroes together as they have to stop Blacksun. Eventually his powers burn out and he collapses, with Doc Savage and his companions returned to their own time before the Thing could get an autograph from his hero.

Like a number of team-up comics where the title heroes are based in different times, this one spends quite a bit of time setting up a situation that can bring them together without leaving too much time for actual interaction between them. It's also restrained by limited and confusing information about just what Blacksun is trying to do or how exactly he gains his powers. Since this is critical to the story's resolution the result is rather unsatisfactory. We're left with a very brief encounter between the Thing and Doc Savage, with multiple sidekicks in tow, with even less time than usual to explore how the two work together. There have been other cross-time team-ups that do a much better job at bringing the two heroes together, whether by having the regular star timetravelling or the guest star catapulted to the regular era at the start of the tale. Alternatively a story can not have the heroes meet and instead show them fighting the same foe in different eras. But here the story tries to both at once and fails at both.