Penpen

Penpen are small penguin robots in Mega Man 3. They mainly appear in Gemini Man's stage (before Doc Robot), and come out of the Penpen Machine. Later they'll be in the water area of the first section of Dr. Wily's castle, where they move up and down until you're close--then they swim toward you.

Penpen Machine
Penpen Machine is the "mini-boss" of the Gemini Man stage (before Doc Robot), and there are two of them. Both are dealt with by hitting the eyes (yes, various walkthroughs say the crank, but I (D-Boy Wheeler) have played the game and hit the eyes, and they took damage that way; perhaps because the eyes were close enough to the crank area).

Similar enemies
Enemies similar to the Penpens.
 * Peng
 * Pengu Bomber