From the Super Mario Wiki, the Mario encyclopedia
Chomp-Munchers are a fusion of Munchers and Chain Chomps that appear in the Nintendo Adventure Book Monster Mix-Up. They are described as having the heads and snarling jaws of Chain Chomps, though instead of chains trailing from them, Chomp-Munchers have leafy stalks like Munchers. Like its two relatives, Chomper-Munchers are aggressive and attempt to attack anything in sight. They were formed by Bowser through experimentation with his Monster Mixer.