Dynamo

Dynamo (ダイナモ) (not to be confused with Dynamo Man in the classic series) first appeared in Mega Man X5; he was sent by Sigma to knock Eurasia out of orbit. He appears twice--in both cases to interfere with the mission (whether it's getting the Enigma ready or preparing the Shuttle).

Dynamo appears again as a secret boss in Mega Man X6, in the Soul areas after Gate's Lab is unlocked and defeating both Nightmare Zero and High Max. Being struck by Rainy Turtloid's weapon causes him to be stunned and a follow-up hit from it makes him drop 200 Nightmare Souls, for a maximum of 600 per fight. Dynamo is a powerful, defensive, and fast opponent, although the ability obtained by Zero from the aforementioned Boss easily makes short work of him. The pre-battle dialogue in X6 shows that he is interested in the power of the Nightmare Souls and how they can make him strong enough to defeat X and Zero.

Dynamo can always be fought every time the player visits any of the Nightmare Areas, allowing X or Zero (possibly even both) to quickly farm Nightmare Souls.

Attack

 * Dynamo jumps to one side of the screen and punches the ground causing lasers to shoot up in front of him.
 * Dynamo spins his saber in front of him and fires multiple spinning sabers, which can either come or don't come back, or follow the player.
 * Dynamo jumps up and swings his saber downward at the player.