A lot of the best things in life come in groups of five. The Jackson 5, for example, had five members. Ben Folds Five didn’t, but they were still good. Other notables: the high-five, five senses, the number of piano concertos by Beethoven, the five-second rule, and the movie The Fifth Element. Another great thing that can come in a group of five? Halloween costumes! Here are some Halloween costume ideas for groups of 5.