Chain Chawfuls are enemies in Mario & Luigi: Bowser's Inside Story. The appearance of the Chain Chawful shows a green Fawfulized Sworm out of a Chain Chomp's head with the eyes being swirly, showing that the Chain Chomp is mind-controlled.
When they are hit, the Fawfulized Sworms hide in the mind-controlled Chain Chomps. The only attack of Chain Chawful is the fawfulized Sworm moving its head up or forward. How many times it swings it head shows how many times Chain Chawful does it. If forward, it goes forward and Bowser must punch it. If upwards, the Chain Chawful hops upwards and Bowser can duck in his shell to counter the attack. Mario and Luigi can counter both ways with their Hammers.
In order for Bowser to defeat it, he needs to inhale the fawfulized Sworm which takes many presses on the "X" button to stop the Chain Chomp from being mind-controlled or attack it until it becomes defeated. One of the Chain Chawfuls on Bowser Path has a Blitty.