This is a small boss for Mega Man Chemical Meltdown that you fight during the intro. In the tutorial level of the game (similarly to Mega Man 7), Mega Man encounters Bass among the reckage of the level. There is a cutscene in which he explains to Mega Man how he stole some of the xenocine from Dr. Wily, which he procedes to inject into his Bassnium. This causes a freak reaction that makes Bass super fast and able to fly, as well as making his eyes visually green. Suddenly, a Yellow Devil shows up and attacks. During the fight, since it has a special xenocine-powered shield device, Bass draws its fire so you can hit it in the back, which is where its shields are produced. After destroying the shields, Bass shoots the Yellow Devil in the eye and defeats it. He then beams away to find Dr. Wily's castle to face Wily directly, where you encounter him later in the game...
Concept and AI scripts all by me @DancingBoi for the circle test Custom Yellow Devil and Bass sprites off the internet, edited by me AI: The Yellow Devil follows a special attack pattern that it regularly repeats. First, it will shoot 3, then 2, lasers in a spread pattern, which Bass will dodge. Then the Yellow Devil will jump forward and Bass will move to the other side of the screen. The Yellow Devil then pounds the ground 5 times, sending shockwaves in both directions. Bass then shoots at the Yellow Devil, who tries to counter with an uppercut punch, exposing its shield generator, allowing you to hit it. It then jumps to forward again, and Bass flies to the other side of the screen once more. The Yellow Devil throws 4 yellow cubes at you, then jumps forward again. It does the earthquake attack again, followed by an uppercut that lets you hit it again. After this, it will jump forward another time, and the cycle repeats. (Note: every time the Yellow Devil jumps, a pound effect plays. This does NOT stun the player, despite this sound.)