Sigma Head

Sigma Head (シグマヘッド) is the first boss of Mega Man X5. He wounded the character opposite to the one the player chose (he destroys X's Force Armor if the player chose Zero, or destroys Zero's buster if the player chose X), and hid inside a statue in the background. It is a giant head of Sigma that sends out small energy spheres from its mouth or energy spheres from the eyes. He can also attack by ramming the character across the screen. After losing half of his energy, he will also send large beams from the mouth. It is only vulnerable at the cannon that appears when the mouth opens. After this boss is destroyed, Sigma's real plot is revealed.

After X and Zero have defeated him, they discover that Sigma lost to them on purpose so he could cover the entire Earth with the Sigma Virus with the explosion. 

Similar enemies

 * Sigma Virus