Board Thread:General Discussion/@comment-176.78.141.165-20161006183419/@comment-209.239.195.92-20171216212502

Joint of Bones Panic wrote: The mosquito scene isn't supposed to make sense. Trying to make sense of that scene defeats the purpose of it being there. The mosquito is a wizard, just leave it at that.

Alternatively, if you want to be super nit-picky, you could argue that Saitama could have atomized the mosquito instantly, but the act of doing so would have leveled the entire city, and the mosquito scene was a tongue-in-cheek nod to his incredible self-restraint.