Spark Man (or Supākuman in Japan) is one of the eight Robot Masters and main antagonists of the NES video game Mega Man 3 as well as the Gameboy game Mega Man III. While originally created by Dr. Light and Dr. Wily as a robot meant to generate electricity, the latter kidnaped and reprogrammed Spark Man into a violent Robot Master.
Mega Man 3
Spark Man is one of the 8 Robot Masters that the player will need to defeat in order to reach Dr. Wily. In battle, Spark Man's weakness is Shadow Man's Shadow Blade. Once Mega Man has defeated Spark Man, the former will obtain the latter's Spark Shock.
After all 8 of the Robot Masters are defeated, Doc Robot will take over 4 of the stages including Spark Man's. Spark Man himself does not appear in the Doc Robot version of his stage. Instead, he is replaced by Doc Robot in the form of Metal Man and Doc Robot in the form of Quick Man. Doc Robot in the form of Metal Man can be defeated by utilizing either Magnet Man's Magnet Missle or Hard Man's Hard Knuckle. While Doc Robot in the form of Quick Man is vulnerable Gemini Man's Gemini Laser as well as Snake Man's Search Snakes.
Spark Man returns for another battle once the player reaches Dr. Wily's fortress. His weakness is once again the Shadow Blade, however, he is also vulnerable to his own Spark Shock. Once defeated for the second time, Spark Man does not return for the rest of the game.
Mega Man III (Gameboy)
Spark Man returns in the Gameboy game Mega Man III. He behaves just like he does in Mega Man 3 on NES, however, there is not Doc Robot or rematch. Because Spark Man never returns as a boss in any other canon Mega Man game after his defeat in Mega Man III on Gameboy, it is safe for one to assume that this is the game where Spark Man is defeated once and for all.
Super Smash Bros.
in Super Smash Bros. 4, one of the Mega Man's attacks is the Spark Shock. In Ultimate, Spark Man appears as an advanced support spirit who increases attack and resistance to energy shots. His spirit battle is a stamina battle against four orange Mega Mans who favors using up special (Spark Shock) in the Midgar stage with an electrified floor.
Spark Man was likely made as a successor to Elec Man. Evidence supporting this includes Spark Man's Mega Man & Bass CD data explaining that Spark Man can generate twice the amount of electricity that Elec Man can. However, the Mega Man: Robot Master Field Guide (which was meant to be a sort of spiritual successor to the Mega Man & Bass CD data) states that while the CD data is true, Elec Man can concentrate his electricity more efficiently, canonically explaining why Elec Man's Elec Beam is more effective than Spark Man's Spark Shock.