Spike Pushers

Spike Pushers (スパイクプッシャーズ) is the boss of Wily Castle 1 in Mega Man 9. They are a series of small, stationary oni-like robots located at the ends of four "corridors". There's a large spiked ball on each corridor the machines continually shoot at, pushing them gradually to Mega Man's side. There are two variations of the Spike Pushers. Spike Pushers B are blue and fire one bullet at a consistent rate, but only push the spike ball a short distance. Spike Pushers R are red and fire a charged shot less frequently, but pushes the spiked ball at a much greater distance. Touching any of the large spiked balls will kill Mega Man instantly, even if the Shock Guard item is equipped.

If either of the Spike Pushers push the spiked ball to the far left of the screen, the ball will retract slightly and it will no longer attempt to push it. Instead, they will aim for Mega Man with a small wave of energy. If Mega Man pushes the spiked ball into one of the Spike Pushers, it will be destroyed and a new one will spawn from the wall until the boss's health has been depleted enough.

Tornado Blow works well against them since it pushes back all the balls at once. However, chances are that the weapon energy will be depleted for that weapon, since it was used to operate the platforms earlier in the same stage, unless Rush is used in its place to save energy. The weapon also uses a lot of energy, so the player won't have enough to defeat the boss entirely with it. Alternatively, Magma Bazooka can be used to hit three spiked balls at the same time, and Plug Ball can be used to quickly hit the spiked ball in the front and the one below.

Trivia

 * This boss is most similar to the Boobeam Trap from Mega Man 2, and are fairly unique when compared to other Mega Man bosses. They are both a number of stationary enemies arranged in a somewhat maze-like room where strategy and planning are more important than reflex and timing. It is also somewhat similar to Atetemino from Mega Man 8, primarily in room design (though it is flipped on its side).