From the Super Mario Wiki
Big Buzzy Beetles are giant varieties of Buzzy Beetles. They first appeared in Paper Mario: Sticker Star and reappeared in New Super Mario Bros. U.
Super Mario series
New Super Mario Bros. Wii
The big, unused Buzzy Beetle.
Giant Buzzy Beetles were originally going to appear in New Super Mario Bros. Wii, but they were removed before the final version of the game was released.
New Super Mario Bros. U
Three Big Buzzy Beetles from New Super Mario Bros. U
While not as large as the New Super Mario Bros. Wii design, Big Buzzy Beetles did eventually appear in New Super Mario Bros. U. They are found in Rising Tides of Lava from Peach's Castle, where they ct as both enemies and platforms. Mario can jump and stand on top of a Big Buzzy Beetle's shell, even while floating on lava when it rises, showing to be immune to lava. They are one of the few enemies that don't reappear in New Super Luigi U.
Paper Mario: Sticker Star
Debuting in Paper Mario: Sticker Star, one Big Buzzy Beetle acts as a mini-boss of Hither Thither Hill, the third boss battle of Decalburg's first world. Mario must defeat it to continue his adventure. In battle, the Big Buzzy Beetle can go into its shell and ram into Mario, just like normal Buzzy Beetles. However, the Big Buzzy Beetle is impervious to all attacks (except for Ice Flowers, which will damage it), with its only weak spot being its underbelly. The boss must be flipped over by either successfully jumping on it or by using a Pow Block sticker. When it's upside-down, the Big Buzzy Beetle can ram into Mario again and bring itself up. It has 40 HP, and drops an HP-Up Heart upon defeat. It is also an optional mini-boss, the only one in the game.
Names in other languages
||Giant Buzzy Beetle