Mormon urban legends or folklore/Cain as Bigfoot
Cain as Bigfoot, or Cain "Translated"
It is claimed that Cain—son of Adam and Eve and the first murderer—still walks the earth today. This appears to be based upon a passage from Spencer W. Kimball's book The Miracle of Forgiveness.
As I was riding along the road on my mule I suddenly noticed a very strange personage walking beside me.... 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 asked him where he dwelt and he replied that he had no home, that he was a wanderer in the earth and traveled to and fro. He said he was a very miserable creature, that he had earnestly sought death during his sojourn upon the earth, but that he could not die, and his mission was to destroy the souls of men. About the time he expressed himself thus, I rebuked him in the name of the Lord Jesus Christ and by virtue of the Holy Priesthood, and commanded him to go hence, and he immediately departed out of my sight....
The Bible implies that Cain eventually died. The idea that Cain still walks the earth is folklore.
There is no scriptural support for the idea that Cain never died
Nowhere in scripture, ancient or modern, is it declared that Cain would or did live beyond his mortal years. No mention is made of his death, but we do read of Lamech, Cain’s great-great-great-grandson, who made the same covenant with Satan that Cain did. This covenant is described as being had “from [or since] the days of Cain,” which seems to indicate that Cain was dead by this time. (See Moses 5:51.)
In any case, the scripture is ambiguous, and so the door is left open for all kinds of speculation about what happened to the man from the land of Nod. And hence began a Mormon urban legend. For what its worth, if an apocryphal source can be trusted at all, the Book of Jasher does happen to give an account of the death of Cain:
And Lamech was old and advanced in years, and his eyes were dim that he could not see, and Tubal Cain, his son, was leading him and it was one day that Lamech went into the field and Tubal Cain his son was with him, and whilst they were walking in the field, Cain the son of Adam advanced towards them; for Lamech was very old and could not see much, and Tubal Cain his son was very young. And Tubal Cain told his father to draw his bow, and with the arrows he smote Cain, who was yet far off, and he slew him, for he appeared to them to be an animal. And the arrows entered Cain's body although he was distant from them, and he fell to the ground and died. And the Lord requited Cain's evil according to his wickedness, which he had done to his brother Abel, according to the word of the Lord which he had spoken. And it came to pass when Cain had died, that Lamech and Tubal went to see the animal which they had slain, and they saw, and behold Cain their grandfather was fallen dead upon the earth. (Jasher 2:26-30)
It is an odd coincidence that in the folklore accounts, Cain appears as some sort of hideous creature, even if he is just a spirit, and in this apocryphal account, his descendants mistook him for an animal. But this is nothing but coincidence. Whatever the case, Cain is definitely dead.
Where did the idea that Cain is "Bigfoot" come from?
The notion that Cain somehow lived on, survived the Flood, and roams the earth today, is familiar to modern members mostly based on a single claim of David W. Patten supposedly meeting “a very strange personage,” dark and hairy, who “was a wanderer in the earth and and traveled to and fro.” (Thus managing to tie Cain to another popular urban legend: Bigfoot.)
This account was published in a biography of Patten written by Lycurgus Wilson in 1900. Wilson had a letter from Abraham Smoot giving his recollection of what Patten said. In historical parlance this is what is called a late, third-hand account—the sort of thing most historians would dismiss. This kind of testimony is simply unreliable, tainted by the passage of time and the fog of memory.
The story probably would have been forgotten if then-Elder Spencer W. Kimball hadn’t included it on pages 127–28 of The Miracle of Forgiveness. Elder Kimball’s book has become a staple of Mormon reading, the book that many bishops give to members struggling with sin and many mission presidents assign their missionaries to read.
The passage where Kimball quotes Wilson is really unnecessary to the chapter itself, which is about unforgivable sins, including murder. He cites several examples of murderers in the scriptures, beginning with Cain. He then throws in, almost as a passing idea, “an interesting story” about Cain.
Matthew Bowman wrote that Wesley Smith, the brother of President Joseph Fielding Smith, was reportedly also almost attacked by a hideous being. He rebuked the entity with his priesthood, similar to the Patten story. He then related the story to President Smith, who naturally identified this character as Cain, basing that identification on the David Patten story. Even if we give Wesley Smith the benefit of the doubt, and grant that some evil spirit made an appearance, using critical thinking we can surmise that there is no justification for even making that identification of Cain. Any evil spirit theoretically could appear as a hideous being. Other folklorish stories are similar in their details.
It appears, according to Bowman, that the conflation of the myths of the wandering Cain and Bigfoot started around 1980 with some Bigfoot sightings in South Weber, Utah, and by 1990, those residents were associating their Bigfoot sightings with Cain. (Journal of Mormon History, Fall 2007, "A Mormon Bigfoot: David Patten's Cain and the Conception of Evil in LDS Folklore", pp. 62-82). An author named Shane Lester has even gone so far as to write a fictional book based on the conflation of these stories called the Clan of Cain: The Genesis of Bigfoot. However, oddly, Lester made the following claim, referring to the Patten story...
A recently uncovered document reveals a possible connection between the origins of the Mormon Church (Church of Jesus Christ of Latter-Day Saints) and Bigfoot. Searching through the archives of historical church documents the author, Shane Lester, uncovered an extraordinary story that becomes the foundation of a new theory about the origins of Bigfoot. "I uncovered an obscure historical document that sheds new light on the Bigfoot mystery. I used this encounter as the basis for a fictional story that links the mystical, legend of Bigfoot to the origins of Mormonism," says author, Shane Lester. 
He is he taking credit for "uncovering" some historical document from Church archives, as if the story is news. The story that he is referring to is unambiguously Elder Patten's story of the encounter with Cain in the first chapter of the book. Lester originally had offered a sneak-peek at that first chapter on his site.  But the story about Patten and Cain has been publicly available since Wilson's book on Patten came out in the year 1900 (a century before Lester wrote his book). Furthermore, the account is anything but obscure. It is well-known because of President Kimball's book. He claims the Cain-is-Bigfoot theory is "new" and that it sheds "new light" on Bigfoot. The theory has been around for several decades now, and it is very unlikely that Lester was the one to originate it. As we just saw in a preceding paragraph, Bowman documented where that came from. Thus, Lester is making claims that are utterly baseless. The Clan of Cain isn't Lester's only book that attempts to link Mormons with occult themes. He also wrote a book on Mormons and a theory linking them to extraterrestrials called The Conversion Conspiracy, which also features LDS folkloric themes. 
Why is it that some LDS people give these stories doctrinal credence? Does that not manifest a measure of gullibility? Is it only because President Kimball quoted it? They give Cain some kind of quasi-translated status based on the story alone, without question, as if he is some kind of hideous undead creature akin to a vampire or zombie that can appear and attack people physically. Why is no skepticism applied to the story, and to the new folklore that has arisen around it? Wasn't Cain a son of perdition, a liar from the beginning? Would someone believe claims from Mark Hoffman? Then why should they believe possible words from the mouth of Cain? As far as can be discerned from the folklore account, Elder Patten did not test Cain by shaking his hand to see if he was truly corporeal. What justification would there be to believe the words of a son of perdition? It doesn't make sense that any good-thinking person would give those claims credence.
- Lycurgus A. Wilson, Life of David W. Patten [Salt Lake City: Deseret News, 1900], p. 50., quoted by Spencer W. Kimball, The Miracle of Forgiveness, pp. 127-128.