It is a bomb that explodes upon contact with any enemy or with a tile. The explosion consists on multiple explosions of cyan color that can cause multiple damage to enemies that get in contact with the bomb. The Flash Bomb will explode even in targets that otherwise bounce off attacks that are unable to damage them either permanently or because it is in a shielded stage. Nonetheless, the explosions will not harm enemies that are in a shielded status nor enemies fully immune to this weapon.
Only two bombs can be present at the same time, and this extends to their explosions. Therefore, if the player had targeted two things in a same screen, the player has to wait the two group of explosions to finish before being able to fire the weapon again. With a full bar, this weapon can be used 25 times.
Similarly to Crash Bomber, its explosive effect deals multiple damage to bosses not immune to it. It will not damage in the invincibility frames, but if the boss does not move too much, the explosions can damage the boss again.
- When used by Mega Man in the original game, the explosions were yellow, but in Mega Man Maker both Grenade Man and the player's versions are blue.