Mondai

and his partner Potcha were two imposters who tried infiltrating Konoha.

Impersonators Arc
Mondai and Potcha went to infiltrate Konoha and gather its secrets by disguising themselves as Might Guy and Rock Lee respectively, while the real Guy and Lee are out on a mission. They are oblivious to the fact that their disguises are fooling nobody, except for Naruto. Tsunade, Sakura, and Tenten force them along by giving them outrageous missions, preventing them from learning anything. They are defeated when the real Guy and Lee attack them with their Double Dynamic Entry technique.

Trivia

 * Mondai calls himself while disguised as Might Guy, which is a pun for  which means "no problem".