Nanabozho is a trickster from the belief systems of the Algonquin tribal groups. His name has a lot of variations, but they all mean something along the lines of “big rabbit,” as that is the form in which he most commonly appears.
As a trickster, he can change his own shape, and can inflict changes in size — if not shape — on his foes if the need arises. Most importantly, he outwits his foes, rather than defeating them in a less subtle manner.
But like other tricksters, he’s usually only out for himself. This can make him gluttonous at times, callous or mocking at others. Sometimes you might think it’s better to run if you see him coming, but other times you might think he’s the best ally you could ever have.
[EDIT: my sources seem to have been muddled regarding this story. Please see the comments sections for details.]
Perhaps his most important — and serious — tale involves an attempt on the life of his grandmother, Nokomis, that is to say Mother Earth. The underwater panthers and the thunderbirds tried to drown Nokomis in a massive flood. Well, Nokomis — being Mother Earth, after all — couldn’t drown, but there were a lot of other creatures that could. So Nanabozho, from his safe perch in a tree, called out to some animals that were excellent swimmers — otters, beavers, and a few species of birds — and asked them to dive down to the bottom of the flood and bring back up some mud from Nokomis’ body. They did as he asked, and Nanabozho (or his helpers acting as his intermediaries) used that mud to create floating islands for all the animals that couldn’t swim, so that they wouldn’t drown. And that, of course, is where the islands and continents all came from.
Nanabozho (re)creating the world is not so easily paralleled, but most of the rest of his lore is very much in keeping with trickster tales from all over the world.
The most famous trickster gods are folks like Hermes and Loki. Other tricksters include Maui from Polynesia/Hawaii, Anansi the spider from western Africa, and Coyote from the American west.
Trying to go into detail would take a very long time. In fact, there are whole books out there just talking about the trickster. Personally, I recommend Trickster Makes This World by Lewis Hyde.