12 Superpowers You Didn’t Know Spider-Man Had
7. Shape-Shifting
Okay, so this wasn't exactly Parker's intention, but Spidey can shape-shift if he ever needs to. Though he may not be in too much of a hurry to go through that again.
During Stan Lee and Gil Kane's incredible run, they came up with the Six Arm Saga, a story that has been revisited a number of times in the comics and animated TV series. It was a pretty logical step, considering you can't exactly be a spider with only four legs, but my goodness was it horrifying for both the readers and Peter.
Having one of his trademark "I don't want to be Spider-Man anymore" meltdowns, Peter tried to create a serum to cure himself. Despite appearing to work correctly, a few days later something deeply unexpected happened. During his sleep, Peter developed four new, fully functioning arms as a consequence of taking the serum.
It's safe to assume he still has the formula written up somewhere. So, if he ever needs to shape-shift again, it's ready and waiting for him. He could even tinker around with different DNA and turn into a strange bird/spider/human hybrid... But let's hope he never does.