Amps (also called Zaps) are small electrical black iron-like balls that appear in several Mario games. If the player touch it, it will be hurt. Yoshi, neither, can't eat him, because of the electricity. The Amps generally, rotate according a circular axis.
In this game, Amps can be defeated if the player uses the Thunder Flower or a Rainbow Star. Using the Thunder Flower, the player can throw thunder balls, overloading the enemy's system with lots of electricity (but in this case, is necessary throw more than one thunder ball). In this game, it's revealed that the Amps are ruled by an giant Amp with a crown: King-Amp. He appears in a secret planet of Atomic Clock Galaxy (World 5) that can be only found if you feed the Hungry Luma with 50 coins. To defeat him, you will need to use the Thunder Flower.