[Envy may have never read a single comic book himself--comic books aren't even a thing in Amestris--but he's actually heard a decent amount of rambling about Spiderman from one of his best friends here.]
[So when he sees a guy in a spidery costume swinging around on what looks like webs, he's pretty sure that yeah, that's totally Spiderman. And when he sees the guy stop to take a break on a wall, he figures he should go check this out. He's not intending to say anything about comics though, because that would be weird.]
[He's got some of his own superpowers, and he uses them to jump up from a lamppost to the building's stone awning, and up to a higher ledge that's sort of close to the guy. At least close enough to be heard when he shouts.]
[action]
[So when he sees a guy in a spidery costume swinging around on what looks like webs, he's pretty sure that yeah, that's totally Spiderman. And when he sees the guy stop to take a break on a wall, he figures he should go check this out. He's not intending to say anything about comics though, because that would be weird.]
[He's got some of his own superpowers, and he uses them to jump up from a lamppost to the building's stone awning, and up to a higher ledge that's sort of close to the guy. At least close enough to be heard when he shouts.]
Hey! Impressive powers you've got there!