Ah, the Medicine of Youth Naruto: Shippûden : Season 9 Episode 186

Back before Rock Lee had his surgery, Naruto, after donning the suit given to him by Guy, set out on a mission with Sakura and Ino to obtain a special flower which was a necessary ingredient for Lee's medicine. When Naruto picked one of the flowers, however, he had to face a strange technique that had taken on the form of Gaara.