Smile

Smile is the emitter Quirk used by Shinjiro Hohoemi, a villain created for the anime special Laugh! As If You Are in Hell. It reaches both close and long range.

Baring the teeth at someone locks that person into uncontrollable laughter for a two-hour stretch. The trigger does not demand a face-to-face encounter, since a reflection in a mirror or a video feed carries it just as well, provided the image is live.

Victims are effectively removed from a fight, barely able to move while the fit runs its course, and some lose their grip on their own Quirk in the process. Shoto Todoroki managed to hold the laughter back and was still taken out of commission, while Katsuki Bakugo knocked himself unconscious. Machines are not immune either, though they short out and break rather than laugh, something Mei Hatsume's capture robot and Power Loader both found out.

Obscure the target's vision and the Quirk accomplishes nothing, so anyone able to fight without relying on their eyes can face the user directly. Enough distance produces the same result.

Shinjiro Hohoemi is the only known user, and the Quirk kept both the Police Force and the Pro Heroes from putting him in cuffs over his vandalism. Distance was his one gap, so he tucked a hologram projector into his hat and threw it, casting an image of his face while a female voice announced "Mr. Smiley!" The lengthy duration and the sheer strength of the effect let him graffiti unimpeded and escape again and again, until the police called on the Endeavor Agency, which found him no easier to bring in. Izuku Midoriya rated the Quirk formidable and figured Shinjiro could have made a great hero with it. Ms. Joke, the Smile Hero, works much the same way with her Outburst Quirk.