Amp did not originate from fanon, and the information on this page may not be entirely accurate to their canon. You may read more about this subject in the context of their canon on the following wiki(s):
Amps (also called Zaps) are small, electrified metal orbs that first appeared in Super Mario 64, later appearing as semi-common enemies on the Mario franchise. The resemble Bob-ombs, though they have a smile as well. Mario can get damages simply by touching one, which will shock him and stun him for a short time. Some Amps are stationary, while others move in a set path. They are immune to any and all attacks save for Invincible Mario, so they must often be avoided at all costs.
Larger Amps, called Big Amps, also appear, making their debut in New Super Mario Bros. U. They behave identical to regular Amps, but their larger size makes them more difficult to avoid.