Clucker, referred to as Kokekko (コケッコー) in the Japanese manual, is a chicken-shaped badnik from the 16-bit version of Sonic the Hedgehog 2 found in Wing Fortress Zone. They shoot eggs from a turret. Jump on their head to get rid of them; their base remains after being destroyed. "Kokekko" is the Japanese equivalent of "cluck".
The enemy reappeared in Sonic Pocket Adventure's Aerobase Zone.
They also reappear in Sonic the Hedgehog 4: Episode 2, in Acts 2 and 3 of Sky Fortress Zone, with a modified design, but with the same attack pattern.
They appear again, in the two versions of Sonic Lost World, and this time not in aerial areas, in this game they get a new cartoon style design. They appear in Tropical Coast Zone 3 and Silent Forest Zone 1 on rails, in mine carts where they shoot projectiles at the player and also appear in Lava Mountain Zone 3, where they play a similar role to the previous games throwing projectiles of their turrets.
They appears again, in Sonic Mania, but this time in Flying Battery Zone, specifically Act 2 that reference, on the outside, to the Wing Fortress Zone and with the same attack pattern.