Dodecaphobia (from Greek dodeka, meaning "twelve") is the fear of number 12. This phobia is very rare and is barely mentioned in the media, often overshadowed by the very common fear of the next number, 13 (see Triskaidekaphobia). Dodecaphobes may be linked to the fear of 2012 phenomenon, where the supposed doom date is in the 12th month of 2012. They may have felt worried when the date was 12/21/12, especially when they believed that end times could occur such as death of a loved one.
There is another, rather strange source of fear of 12, that if we put the random-number generator into a loop, the loop will not stop unless if it stops on a number other than 12. So the number 12 represents the symbol of infinite loop, so the fear of 12 is linked to the fear of never-ending cycle.
Sufferers would try to avoid encountering the number 12. Many dodecaphobes would want to change the number of months in a year, such as having 13-month years suggested by Scott Flansburg (The Human Calculator). They would also add Ophiuchus as the sign of zodiac to increase it to 13. Some sufferers would want to use the 24-hour clock (which has 24 different hour numbers from 0-23) as they think that calling the same hour number twice a day is not right (e.g. 12:12 occurring twice a day). If dodecaphobes realize that the average size of human foot is actually 10 inches, not 12 inches, they would define foot as a unit equal to 10 inches.
In some cases, a phobia of the number 12 could mean that sufferers get chills down their spine thinking about Tom Brady beating their team.