The creature known as "Gotch-Eye" (a colloquial name) lived in the bayous of southern Louisiana. It is believed to have been created to live in extraterrestrial environments, but it got loose after skydark and found a new home on Earth.
Gotch-Eye was huge, though its size (and, actually, appearance) are a matter for debate, since it lives underwater. It has several tentacles lined with tendrils like a man-o-war's that exude highly toxic poison, a single large eye, and a mass of seaweed-like acidic tendrils that it uses to dissolve its prey. (Haven's Blight)