The Canadian Invisible Shell-wearing Coconut Crab or "Invisible Birgus/Birgus nanidesukus" is a "cryptid" urban myth from Nova Scotia Canada reported to climb into peoples apartments through open windows and steal food. It isn't truly invisible but rather is called so in reference to it's impeccable hiding skills.
The story goes that the creature enters apartments by using its powerful limbs to scale railings or drainage pipes and climb through open windows or balcony doors. The stories were popular among students from around 2009-2013 but have since fallen into obscurity.
The Invisible Birgus is not truly invisible, rather it's named for it's skill in concealing itself and to get in and out of spaces unseen, even opening doors and cupboards if the knob is a handlebar. It looks similar to a typical coconut crab but substantially smaller in size and sharing it's smaller relatives habit of wearing discarded shells, typically those of moon snails (one of the few native gastropods to posses large enough shells). Descriptions are vague but a 20 centimeter leg span seems to be typical, the body is often compared in size to a small pigeon. It eats primarily fruit but has also been reported taking grains and bird eggs.
As the myth is originating from urban Nova Scotia, it's probably based on accounts of escaped tropical hermit crabs or coconut crabs, as the only native hermit crabs are aquatic.