We've never seen this guy before, but we're going to launch him on a round-trip of the time stream; I'm sure he'll be fine.

And he's pulling focus from the bikini-girl hijackers! From 1977, Superboy and the Legion of Super-Heroes #233, "The Infinite Man Who Conquered Time the Legion!" Written by Paul Levitz, pencils by James Sherman, inks by Bob Wiacek.

After a brief scuffle with Sklarian technology raiders--well, let's unpack that for a second: they were apparently Prime Directive'd out of getting the fancy earth tech, and they wanted it. I don't know if they were recurring foes, but I think Kono from the Five Years Later run was a Sklarian. The Sklarians were probably biting off more than they could chew by trying to take Star Boy and Lightning Lad, but with Superboy present as well they're wrapped up in four pages.

The Legion is helping recurring supporting cast member/honorary Legionnaire Rond Vidar, at the Time Institute, with an experiment meant to prove time was circular. I feel like this would be dangerous even if they sent lab rats, but they send volunteer Jaxon Rugarth on a round trip through time, and of course he returns as an omnipotent lunatic hellbent on revenge on Vidar. That doesn't explain the Infinity Man's headgear, though. And after that scan, I gotta admit I probably would've volunteered for that thing, if they promised a date with Phantom Girl there...

The Infinity Man summons tanks and dinosaurs, freezes Star Boy in time, launches Superboy out of this dimension; but then takes a break to hone his abilities. Team leader Wildfire figures he won't try to kill Vidar in the past, but splits the party, sending some of the less-combat-useful members in search of help. (I don't think he had been leader long, but this issue seems to be establishing Wildfire's management style: good in a crisis, poor at interpersonal stuff and getting worse...) Typical for comics, no help is forthcoming, except it gives Brainiac 5 the idea for overloading him. Rond launches the Infinite Man back through the timestream and traps him, although he and Brainy pledge to try and cure and rescue him. Which they don't, even if they do bring him back later.

In the back-up feature, "The Final Illusion," Princess Projectra is sinking into a coma, since she's been trapped in her own illusion-casting powers. Saturn Girl telepathically determines she's escaping reality since her boyfriend Karate Kid had gone to the 20th century (and his own series!) and Dream Girl suggests turning Projectra's dream into a nightmare. This doesn't quite work, until Chameleon Boy suggests a slight adjustment: in her nightmare, Karate Kid saves her, but then she realizes he was only an illusion, and would have to wake up for the real thing. (They would get married in 1983's Legion of Super-Heroes Annual #2.) 

Rond Vidar would make many appearances over the years: he was later revealed to secretly, and illegally, be earth's Green Lantern, in Legion #50. Post-Crisis, in the Five Years Later run, when Andromeda replaced Supergirl in the Legion and as Brainiac 5's crush object, he was also the father of Andromeda's child! Fans may not have loved that reveal, since Rond would later be killed by surrogate aggrieved fanboy Superboy Prime. Which may be where he stands now, but Legion continuity is of course on the iffy side.