Up'n'Down (アップンダウン App Un Daun) is a small robot from Mega Man 4 and Mega Man III. They emerge from pits to try to knock Mega Man into the pits when he tries to cross without defeating them. In Mega Man 4, they appear in Dust Man's stage and in the first and fourth areas of Dr. Cossack's Citadel. In Mega Man III, they again appear in Dust Man's stage and in the final level.
Kaminari Kogorō (literally "Thunder Infant"), unlike Up'n'Down, can call on thunder bolts to shock Mega Man. They are in Mega Man 7, mainly in Cloud Man's stage and the first Wily Stage. They also appear in Mega Man: Battle & Chase as items that can slow opponents for a short time. In Mega Man 2: The Power Fighters, they will appear during the battle with Elec Man.
Shururun (シュルルン) is an enemy from Mega Man 8 and Mega Man & Bass that acts similar to Up'n'Down, but faster and sports a structure similar to a spiked collar around it. Whenever Mega Man destroys one, another will appear momentarily after a few seconds.