Lizard breath

I heard someone call someone "lizard breath". What does it mean and what is the origin?

I don't know a specific origin for this phrase, but it's clearly meant as an insult, either real or facetious. I seriously doubt the breath of a lizard is any worse or more offensive than that of a cow or cocker spaniel, but humans have a deep-seated fear and distrust of lizards, and we are willing to attribute lots of evil to them. (Cows and cocker spaniels look a lot more like people than komodo dragons or garter snakes, so we respond accordingly.)

Apparently the breath of a Komodo Dragon is unbelievably awful. The meat on which it feeds decays around its teeth - to the extent that a bite from one, if not fatal in itself, is likely to prove deadly by reason of the infection it starts up.

DFG