Cain is Bigfoot
The Church takes no official stance on this, but some members believe that the legendary Sasquatch (or Harry Henderson as I like to call him) is Cain. The main source that usually is used to back this theory is the reminiscence of Abraham Smoot of a story from one of the Church's first apostles, David W. Patten. Patten claimed that in 1835 he encountered Cain walking along the side of the road. He wrote: "He walked along beside me for about two miles. His head was about even with my shoulders as I sat in my saddle. He wore no clothing, but was covered with hair. His skin was very dark."
I can see how someone could get Bigfoot from that description. The Smoot/Patten story was also quoted in Spencer W. Kimball's book, "The Miracle of Forgiveness". In the 1980's, there was a Bigfoot sighting in South Weber, Utah and many members used this story to explain how and why these sightings occurred.