Lambo vs. Rauji Ooyama is the 311th chapter of Akira Amano's Katekyō Hitman Reborn!.
Synopsis
Lampo's Shield (V.V.G)
As the 15 years old Lambo begins to understand the situation, Large Ooyama begins to explain the rules and his pride being his body that had never lost a match. Rauji then activates his Flame of The Mountain, which gives the appearance of a volcano erupting. Using its Flames, Rauji forms a set of jaws that he believes to be powerful and unmoving similar to a Stag Beetle. Lambo begins to sweat at the sight of his opponent, causing Tsuna and Gokudera to voice their worry.
However, Lambo tells them to quiet down since he is about demonstrates his own pride. Tsuna, Gokudera and Reborn watch, holding their breath, but end up surprised when Lambo reveals that his pride is to never refuse a single invitation to go out and party. Tsuna and Gokudera continue to panic, but Lambo is serious and tells them that he will not run away from the fight, he will stand there and handle it. Gokudera tells him to use his Vongola Gear, informing him that it's his weapon. Lambo examines the helmet and sees the face of his bull, Gyuudon, and puts it on. With the help of Tsuna and Gokudera, Lambo activates his helm with his Thunder Set and summons Gyuudon Version X. Lambo then uses its Cambio Forma which makes Gyuudon fuse with him and form the Lampo's Shield (V.V.G), which is a set of armor with massive horns which Lambo commented as "heavy". After Lambo activated his Vongola Gear, he begins to trip and accidentally hits a switch that changes the armor's horns into a new shape, called the Wide Horn. Lambo and Rauji then charge at each other, both refusing to lose to the other...
Characters
*Note: Bold + Italicized = First Appearance