Putrid Haunt

These shambling corpses have twigs, branches, and other debris intertwined with their bodies, and their gaping maws often crawl with scrabbling vermin.
Swamp Undead. Putrid haunts are walking corpses infused with moss, mud, and the detritus of the deep swamp. They are the shambling remains of individuals who, either through mishap or misdeed, died while lost in a vast swampland. Their desperate need to escape the marshland in life transforms into a hatred of all living beings in death. They often gather in places tainted by evil deeds.
Mossy Islands. When no potential victims are nearby, putrid haunts sink into the water and muck, where moss and water plants grow over them and vermin inhabit their rotting flesh. When living creatures draw near, the dormant putrid haunt bursts from its watery hiding spot and attacks its prey, slamming wildly with its arms and stomping on prone foes to push them deeper into the muck. There’s no planning and little cunning in their assault, but they move through the marshes more freely than most intruders and they attack with a single-mindedness that’s easily mistaken for purpose.
Leech Harbors. Putrid haunts create especially favorable conditions for leeches. They are often hosts or hiding places for large gatherings of leeches.
Undead Nature. A putrid haunt doesn’t require air, food, drink, or sleep.