Ningame

is a large red tortoise with red swirls on his shell capable of speech and Might Guy's personal summon. Ningame watches over Rock Lee when Guy isn't around.

Chūnin Exam Arc
He was summoned when Lee challenged Sasuke Uchiha prior to the Chūnin Exams, and prevented the former from opening the Eight Gates. Guy appeared on top of the tortoise shortly after.

Confining the Jinchūriki Arc
Guy summons him while chasing after Kisame Hoshigaki, where Ningame complains that this is the first time he has summoned him in years, and the fact he did so in mid air.

Trivia

 * It could be considered ironic that Guy's summon is a tortoise. Tortoises are normally regarded as slow while Guy's entire fighting style focuses around speed and agility.
 * Ningame is one of ten summons that wears a headband, suggesting that his loyalty is strictly to Konoha. The other nine are Hiruzen Sarutobi's summon Enma and Kakashi's eight ninken.
 * Ningame has only been summoned once during the series, and even then it was off screen, keeping with Guy's habit of only being seen using taijutsu, until chapter 506.