An boa constrictor illegally released into the wild. People buy them when they are small, without realizing their potential size. When they grow too big to handle, they are dumped in the swamplands. Not native to the area, they wreak havoc on the land and it's natural resources.
Just an example of how big these snakes can get when not confined to an aquarium tank.
The Mangroves we were trying to protect, native plants to the Everglades.