What's your favorite non cannon quirk you've read in fanfiction?

One of my favorite things about reading bnha fics is finding out the mc's quirk and seeing how they use it. I find it so interesting and it's easy to get invested with an mc that manages to use their quirk to its fullest potential.

And with how many different kind of fics their are for bnha, where you have oc's with their own unique quirks, or ourwrite give a different quirk to Cannon characters, theirs so many to see.