Weekly Beasties: Poison Pineapple (d20)
A tree-like creature similar in semblance to a pineapple palm tree¸ the Poison Pineapple starts off as a small and mobile plant. When it matures¸ it finds a river or stream to put down roots and serve as its permanent feeding ground.
Once it's rooted it leaks an acidic nectar that taints the waters. Once the river's sufficiently murderous¸ the Poison Pineapple will suck the waters back in¸ consuming the carcasses of the creatures that died in its soup.
Though it only happens once every few years¸ the Poison Pineapple will sometimes grow seedlings. If they survive the drop to the ground they'll hatch into new Poison Pineapples. They're also lethally toxic¸ as many unfortunate souls have discovered when trying to take a bite from the tree's "fruit."