Big Amp

The Big Amps (or Mega Amp) are large sub-species of Amps. They first appeared in Mario Party 5. Regardless of their size, they have the same designs (excluding Super Mario Galaxy). They are redesigned in New Super Mario Bros. U, looking similar to the normal-sized ones from New Super Mario Bros. Wii, though they are few times bigger.

Super Mario Galaxy
Big Amps appears in Super Mario Galaxy as faceless orbs unlike the regular-sized ones. Despite that, they will still act the same way as in the other games, and they will move as well.

New Super Mario Bros. U
Big Amps make their Wii U debut in New Super Mario Bros. U. They behave exactly like normal sized Amps, except they are few times bigger now. There are plenty of them in Snake Block Tower alongside their original counterpart. If Mario touches one, he will get electricuted.

Mario Party 5
Big Amps first appears in Mario Party 5. They appear in Shock Absorbers, along with their normal sized Amps. At first, they are a little bit bigger than a normal Amp. Touching them will electrify the player.

Mario Party 6
A single Big Amp makes a cameo appearance in Mario Party 6, during the intro of Circuit Maximus. It is the first time a Big Amp is very large.