Eri in Boku no Hero Academia is a young girl whose quirk is a the center of production of a quirk canceling drug.
In chapter 156, what exactly Eri's quirk is somewhat revealed. The chapter says that it is "a quirk that rewinds."
She's shown, possibly unintentionally, undoing Chisaki's fusion and her father when trying to reach for her "just up and vanished."
The part about Eri's father is displayed over a panel of empty clothes, so it's possible she rewinded/regressed her own father to the point of being unborn.
http://mangaseeonline.us/read-online...6-page-14.html
It looks like we'll see more of it in the next chapter.