Swampa

It moves through the deep swamp with surprising power and speed, propelling itself with strong limbs through water and muck alike, and it hunts actively now, running down prey through the flooded tangle it knows better than anything else alive. It can still meld into the mud when it chooses, but it more often relies on ambush from the reeds and a sudden overwhelming rush. It shapes its wetland to suit itself, damming channels and wallowing out deep pools, and a stretch of swamp with a resident Swampa is a stretch of swamp remade, quietly, to that one creature's liking.