Yellow Devil

Yellow Devil (イエローデビル), (also known as Rock Monster or Yellow Demon), is one of Dr. Wily's creations, originally a fortress boss in the first Mega Man game. Consisting of a large yellow blob, he can dismantle himself and cross the screen to attack his enemies. His weak point is his eye.

The Yellow Devil can be very difficult to defeat, due to his complicated attack pattern, and his tendency to change forms after getting hit once or twice.

Mega Man Powered Up
In the Mega Man remake, Mega Man Powered Up, it is revealed that the Yellow Devil can talk, but the only thing he can say is "Bumo", which he says in various ways in order to form his own language. Cut Man was seen attempting to speak it, but without much success. His attack pattern is different from the original.

The Power Battle & The Power Fighters
In the arcade games Mega Man: The Power Battle and Mega Man 2: The Power Fighters, he appears as the penultimate boss of the courses "Mega Man 1~2" and "Mega Man 3~6" from Power Battle and "Rescue Roll!" from Power Fighters. He has new attacks such as shooting beams from his eye, separating into smaller versions of himself, walking, jumping, throwing a part of his body that bounces across the room, and absorbing players with his arm to launch them.

Mega Man: Battle & Chase
Yellow Devil is one of the three enemy racers (the others being a Roader and Sniper Joe). There is also a secret boss recolor of him called Black Yellow Devil (ブラックイエローデビル), sometimes shortened to Black Devil.

Other appearances
He also makes a cameo appearance in the opening cutscene of Mega Man 8.

Damage Data Chart
Displays the amount of damage in units that Yellow Devil will receive from each Special Weapon from the original Mega Man.

Mega Man Megamix
Yellow Devil appeared in the manga Mega Man Megamix. After the defeat of Dr. Light's six Robot Masters, Yellow Devil holds Mega Man as he meets Dr. Wily. Wily tries to convince Mega Man join him, but as he refuses, he orders Yellow Devil to crush him. Mega Man manages to escape Yellow Devil's grip by using Guts Man's strength, breaking his arm, and then finishes him off with a Thunder Beam.

Trivia

 * A glitch in Mega Man 1 allows to quickly defeat Yellow Devil by shooting him with the Thunder Beam, and tapping the pause button when it makes contact:every time pause is toggled it will register a hit.
 * The music that plays during the Yellow Devil battle in Mega Man: The Power Battle and Mega Man 2: The Power Fighters is a remix of the music from the first two Wily stages in the original Mega Man.


 * In the U.S., Yellow Devil's name was changed to "Rock Monster" due to a policy Nintendo had against religious references in NES games at the time.


 * In most of his appearances in different Mega Man titles, Yellow Devil's primary weakness tends to be electricity-themed weapons. The Green Devil and Shadow Devil bosses from Mega Man 8 and Mega Man X5 also have an electric-based weakness; Thunder Claw and Tri-Thunder respectively, with Tri-Thunder acting almost identically to his weakness in the original Mega Man, the Thunder Beam.