Pi Phi's symbol is the upward pointing arrow, which of course can't be explained.
Our mascot is the angel. This is what our national website says about why we chose the angel.
"Fraternity history indicates that songs about Pi Phi angels became popular in the late 1930s and early 1940s, and that skits depicting Pi Phis as angels were often used in rush. Angel collections are popular among many Pi Phis. The Founders did not choose the angel as a fraternity symbol; however, it is a worthy unofficial symbol of Pi Beta Phi."