From WiKirby, your independent source of Kirby knowledge.
Great Gear is a twice-appearing mid-boss in Kirby Mass Attack. In its first appearance in Stage 6 of Sandy Canyon, the Great Gear appears only to be an obstacle which the Kirbies must push through the level. When the gear reaches the end, however, it is pulled into place and awakened, upon which it attacks the Kirbies. Its weak point is a blue plate covering the gear's inner mechanisms; however, this plate can only be attacked when the gear is upside-down. Great Gear holds itself in place with a number of weights on change (some of these are larger than others or have retracting spikes) and tends of the Kirbies with spiky fruit from its mouth. Three attacks on the internal mechanisms are enough to defeat the Great Gear.
The Great Gear appears again, though, this time in Stage 9 of Volcano Valley. The battle is the same except that the gear releases Mummbons and, after the first hit, covers the floor in quicksand.
The Kirbys expose Great Gear's weak point.