Two of the most iconic, famous, and beloved superheroes in all of comics are Marvel's Spider-Man and DC Comics' Superman. The characters are two of the most recognizable comic book heroes in pop culture. However, it's easy to mix them up - at least if you're Doctor Octopus.
Doctor Octopus made his first appearance in Amazing Spider-Man #3 by Stan Lee and Steve Ditko. In the book, during an experiment gone wrong, scientist Otto Octavius has four robot arms fused to his body. Otto's brain is damaged through radiation exposure, which gives him the ability to control the metal arms. However, it severely impacts his psyche, which leads him to take on the Doc Ock moniker.
Spider-Man goes to check out the locked-down hospital Doc Ock was staying in and has subsequently overtaken, holding nurses and staff members as prisoners to help him with his experiments. Spider-Man intervenes and tussles with the six-armed villain. Doc Ock manages to slow down Spidey, snapping the web-slingers webbing, as he struggles to deal with the villain's extra arms. As he holds Spider-Man in the air, he proclaims "and now Super-Man, I grow bored with this game!" Um... excuse me?
It's unclear whether Doc Ock is calling Spider-Man "Super-Man," as a joke, or whether this was an error on behalf of the writers and editors. It should be noted, that in later reprints of the story, the line was changed from Super-Man to Spider-Man. So, it seems it was an error that made it past print and was later fixed. If it was a joke, it's weirdly out of place. Just a few panels before, Doc Ock refers to Spider-Man as Spider-Man. There's no wordplay or reference that would suggest 'Super-Man' was the intended choice of name here. Mistakes happen - this one just happened to be quite big.
Spidey did take on the Man of Steel in 1976's Superman vs the Amazing Spider-Man DC Comics/Marvel crossover by Gerry Conway, Ross Andru, Neal Adams, John Romita Sr. Dick Giordano, Terry Austin, and Bob Wiacek. That issue also features Spider-Man trying to take down Doctor Octopus - although it exists outside both DC or Marvel canon. So, while Spider-Man and Superman have met and battled against each other and together as a team, the reference in Amazing Spider-Man #3 is simply an error (or joke) that was later corrected. Regardless, "Super-Man" plays a part in early Spider-Man history - even if unintentionally.