From the Super Mario Wiki
Plant Chompers are enemies from the game Virtual Boy Wario Land. Their behavior resembles the Munchers of various Super Mario side-scrolling games, as they are immobile creatures that appear to be attached by the roots to blocks, and they continuously chomp their jaws. Plant Chompers are seen in Stage 7, often in large areas where Wario must safely cross by riding a Tweester. Their figures are also seen along the bottom of quicksand areas, harming Wario if he sinks too low in the quicksand. Their figures in the quicksand are also seen inside the Guard's room in Stage 8.