Choker Oh

Chokero is an odd hopping robot in Mega Man 6, and it first appears in Centaur Man's stage--specifically, in the area where the water is in the upper half of the screen. They open a lid on their heads to shoot and then hop toward Mega Man.

Chokero (X series)
Unlike its classic predecessor, this version of Chokero stays still, but it's larger, and it can send sparks on the floor (or above ground) and launches missiles.