n. The alter ego of an Irish College student.
-A Shannon O'Houlihan usually appears when one is under the influence of alcohol.
-Once a Shannon appears he is known to make the person extremely loud, rude, and in some cases high.
-A Shannon O'Houlihan is an absolute champion of the game of Beirut (also known as Beer Pong). He has been said to quote that he "pwn3s fools" in the college sport.
-A Shannon O'Houlihan is known to enjoy many fine tasting alcoholic beverages. This includes, but is not limited to: Guiness, Smithwicks, Paps, and various Samuel Adams brews.
-A Shannon O'Houlihan can be very violent at times, use extreme caution around him.
Person 1-"Oh boy he is pretty wasted..."
Person 2-"Let's just hope he doesn't turn into a Shannon O'Houlihan.