Iwagen (rock generator) is an unused enemy in Pikmin, as it's name indicates, generates roscks like an Armored Cannon Beetle, it hasn't an HP counter and was posibily planned as an obstacle. It can found in some unused stages like testmap.
Video
As every enemy animation test, the area where it shows is Animtest: {{#ev:youtube|v=FpNXS37RJjA}}