On "Friends", what distinctive feature does Chandler have on his body?

On "Friends," Chandler has a third nipple on his body.

Chandler Bing's unusual feature is revealed during the second-season episode "The One with Phoebe's Husband." The character jokingly calls it a "nubbin," and his friends become fascinated and amused by the tiny extra nipple. The revelation becomes one of the show's recurring body-related jokes about Chandler.

The storyline later returns when Chandler decides to have the extra nipple removed. That decision produces another round of jokes, including the memorable line about having "two nipples and no waiting." The feature is therefore part of the show's fictional continuity, rather than a one-episode mistake or a detail about actor Matthew Perry.

A third nipple is a real human congenital variation, medically known as a supernumerary nipple or polythelia. It can appear anywhere along the embryonic milk line and is often harmless. In the sitcom, however, the point is primarily comic: Chandler's supposedly embarrassing secret becomes another target for the friends' teasing.