Gumberoo
The Gumberoo is a creature from Lumberjack Folklore. They are larger than bears and looks like walking footballs with leathery skin. Their skin can withstand any attack, even bullets. They can be killed if you set them on fire and wait for them to explode.
Citations:
Bane, Theresa. Encyclopedia of Beasts and Monsters in Myth, Legend and Folklore. United States, McFarland, Incorporated, Publishers, 2016.
Matthews, John, and Matthews, Caitlin. The Element Encyclopedia of Magical Creatures: The Ultimate A-Z of Fantastic Beings from Myth and Magic. United Kingdom, Harper Element, 2009.
Rose, Carol. Giants Monsters and Dragons: An Encyclopedia Of Folklore Legend And Myth. United Kingdom, WW Norton, 2001.