GearBank

GearBank (ギアバンク) is an enemy from Mega Man Zero 4. It appears as the sub-boss of Hibernation Chamber, Fenri Lunaedge's stage. It has four hatches. Each hatch spits out a stream of Serpent Gears that follow Zero, hence the name GearBank. The more Zero damages it, the faster the gears run at him. The player has to destroy all four hatches to defeat it. 

Serpent Gear
Serpent Gear (サーペント・ギア) is the Mechaniloid spat out by GearBank in an attempt to run over Zero. They drop parts when defeated.