Chaos Cannon is a Master Weapon usable exclusively to Shadow Man that appears in the Mega Man and Sonic the Hedgehog comic crossover event, Worlds Collide, published by Archie Comics. Essentially a robotic version of Chaos Control, Chaos Cannon allows the user to trap their foe(s) in a giant bubble-like substance filled with Chaos Energy. Although it is Shadow Man's exclusive Master Weapon, Mega Man can also use the Chaos Cannon Master Weapon for his own usage if Mega Man copies the Master Weapon with his Copy Chip from the Roboticized Master.
When Mega Man uses this move, his regular blue color scheme is switch to a red and black color attire, similar to the color scheme of Shadow Man's non-roboticized counterpart, Shadow the Hedgehog. It should also be noted that every time Mega Man uses Chaos Cannon, he then shouts "Chaos Cannon!". This is a nod to how Shadow the Hedgehog will shout "Chaos Control!" when he is using the said move.
To this date, Chaos Cannon has only appeared in Worlds Collide, and with the natural events of Mega Man's world restored, it is assumed that Chaos Cannon will not appeared again in the Mega Man comic series.