To dream that you or someone else is being beheaded signifies poor judgment or a bad decision that you have made and regretted. You are not thinking clearly and are refusing to see the truth. You need to confront the situation or the person despite the pain and discomfort you might feel in doing so. The dream also suggests that you have the tendency to act before you think.
To dream that a snake is being beheaded indicates that you are refusing to face your fears.