Penpen (ペンペン,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 Maker. Later they are found in the water area of the first section of the Wily Castle, where they move up and down until Mega Man gets close - then they swim toward him.
In Mega Man: Battle & Chase, there are unnamed penguins that act and looks like Penpen, suggesting it's a variety of them. They mainly appear in the South Pole Course.
Penpen EV (ペンペンＥＶ,PenPen EV?) is an upgrade of the Penpen. It spins around, and can be pushed aside with a few shots. But if left alone it will face Mega Man, get on its belly, and do a short gravity-defying jet boost to slide towards him. In Mega Man 8, Penpen EVs mainly dwell in Frost Man's stage. Many appear from the ice blocks that emerge from hovering Hogales. In Mega Man & Bass, Penpen EVs appear in Cold Man's stage.
Penpens appeared in the sewers of the Wily Castle in Mega Man #46.