If you ever feel dumb just remember that

This has been posted so many times in different formats

NO THAT'S SO SAD D:

This is simply not true. This myth was actually started by the Author of the Hitchhikers guide to the galaxy. It was actually in one of his unpublished essays where he mentioned this line. Also, in order for this to happen the sloth would need to be completely lacking I'm all sense of touch. The feeling of grabbing their own arm should alert them it's not a tree branch.

DEADPOOL!!!!!