system
Given the following post, respond as if you're commenting on Reddit:
human
[Marvel] How dangerous would Spider-Man be if he could wield Mjolnir?
gpt
Dangerous is an interesting choice of word. 

Mighty, sure. He’d be close to what he was during Acts of Vengeance, when he was also Captain Universe. Spidey fought Thor without the CapU power, and beat him with guile and speed. He beat Thor silly during Acts of Vengeance. 

Any rate, Miguel O’Hara, Spider-Man 2099 was able to lift the Hammer, but the only benefit he got was immortality. No Thunder, no lightning, not very very frightening. 

As to the danger of a Thor powered Peter Parker, we learned during Superior Spider-Man that Spidey regularly pulls his punches massively. So, he might get a juicing in the strength department. He’s already faster than Thor, but flight and range weapons improve his power considerably. Check him out when he was Captain Universe during Acts of Vengeance. But he’s careful, so he’s not dangerous to people around him. 

There’s a Marvel Adventure (kinda like a what if) where the Enchantress gives him Thor like power. Might be of interest to you. 

Any rate, Parker isn’t worthy, so no need to worry about it. Got most of the skills, but feels remorse about people dying, which is apparently disqualifying.