The Keeper, known as Goarikeeper (ゴーリキーパー Gōrikīpā) in Japan, is a miniboss in Mega Man 10. It consists of a large soccer goal-like area with a head on top and two large fists. It appears twice in Strike Man's stage.
The Keeper attempts to smash Mega Man with its fists, which create stunning shockwaves. After each fist pounds the ground, Mega Man can jump onto it and be raised high enough to shoot the head. In its second appearance, The Keeper also has electric fields on its posts so that Mega Man's movement is restricted to a smaller area.
On Normal and Hard Mode, bouncing soccer balls accompany the fists as they attempt to pound Mega Man.
The key to defeating The Keeper is moving around to avoid damage from the fist and soccer balls and then jumping onto the lowered fist before being stunned. Mega Man can then damage the head before repeating the process. It typically takes three fists to completely destroy the head. Also in Challenge Mode or revisiting the stage, Rebound Striker does well.
The Commando Bomb also works well, the player should fire it upward and then aim to the side where the shockwave of the bomb will hit the head. Two or three Commando Bombs should do the trick.
Bass has an advantage against The Keeper as he can fire vertically, removing the need to jump on the fists.