Triskaidekaphobia is the fear of the number 13. This superstition is common in many cultures, where the number is often associated with bad luck. For example, some buildings skip the 13th floor, labeling it as 14 instead, to avoid unsettling residents or guests. The origins of triskaidekaphobia may stem from various historical and religious beliefs. In Christianity, the number 13 is linked to the Last Supper, where Judas Iscariot, the betrayer of Jesus, was the 13th guest. This fear can lead to anxiety and avoidance behaviors, particularly on Friday the 13th, a day considered especially unlucky.