Changkey,[1] also known as Tackle Fire,[2] is an enemy first appearing in the original Mega Man. It resembles a flame with eyes, with the ability to fly high up into the sky and float down, though official info indicates it is actually a robot surrounded by fire.
In Mega Man, Changkeys appear only in Fire Man Stage, flying out of the lava in certain sections. Three Changkeys in sequence will be launched straight up and leave the screen at the top, then slowly float down, drifting either to the left or to the right at random.
Though they can be destroyed in a single shot while floating down, they cannot be harmed while going up, and Mega Man's shots go through them. They also will respawn indefinitely while their spawn point is on the screen, similarly to "pit jumper" enemies like Up'n'Down and Shururun.
Mega Man 2
Changkey Maker from Mega Man 2.
While Changkeys do not appear on their own in Mega Man 2, the new enemy Changkey Maker uses them as ammo, throwing an endless supply at Mega Man in an arc. These thrown Changkeys cannot be destroyed, but shots go through them, as with most other projectiles. They are only found in Quick Man's stage.
Mega Man: Dr. Wily's Revenge
Sprite from Dr. Wily's Revenge.
In Mega Man: Dr. Wily's Revenge, Changkeys once again appear in the game's version of Fire Man Stage, though acting quite differently. Rather than being launched up and floating down, they instead fall endlessly from dispenser tubes hanging overhead, always going straight down. They can also no longer be destroyed and deflect Mega Man's shots, which can sometimes block him from hitting other enemies.
Changkey Makers from Mega Man 2 also return, again with the distinction that the Changkeys they throw can deflect shots. Though Changkeys by themselves appear only in Fire Man's stage, "Makers" are also found in Wily Stage 1 and Wily Stage 2.