AR in Honto ni Atta! Reibai-Sensei
 

I was browsing through Google to find interpretations of the classic Fountain of Youth Japanese tale when I found some unexpected and cute (but sadly poof) AR in a manga called Honto ni Atta! Reibai-Sensei.

From what I can gather, the manga is about a young female teacher named Kibayashi-sensei "whose hobby is speaking with the dead and whose special talent is exorcism. Kibayashi-sensei knows everything about the other world, but nothing about our own world." (Lifted from Baka-Updates)

I can't understand Japanese so I'm not sure about the context, but in a chapter in volume 10, Kibayashi-sensei accidentally spills some youth water on herself, and ends up turning into a child. Since her mind is apparently partially changed as well, she ends up behaving like a child, pouring the rest of the youth water in a water gun, and squirts it all over her students, causing mass AR to kids. There's no RN scene, but the next chapters show everyone as their normal ages again, so I assume they turned back offscreen.

Like I said, it's sadly poof, but it's really cute and with baggy clothes, so it's still pretty good. The manga was adapted into an anime, but this chapter apparently wasn't, since my searches for an anime equivalent proved fruitless.

Re: AR in Honto ni Atta! Reibai-Sensei
 

wow nice find! been a while since saw a lot of people AR in manga usually only few persons are involved