The name is a combination of "iwa" (meaning "rock") and "gen" (short for "generator"). It has no health counter and its only animation is for shooting. It appears to be a rock spitting vase, shooting small boulders similarly to the armored cannon beetle. In some test levels such as testmap, there is an unused enemy called 'iwagen'. Specifically: Replace images with better ones and/or GIFs. There's a whole lotta words here, but not enough pictures. You will have to restart the game to leave the debug menu. To access this, use one of the codes below, then hold the D-pad right when loading a menu.
Pikmin is the story of Captain Olimar, an explorer who crash lands on an "unknown planet" (that totally doesn't resemble Earth in any way). This game has hidden development-related text.