Friends in your contacts on your phone who only send you forwards, and when you really want to text them, they never text you back (Especially right after a forward.)
Robert: Ooh! A new text from Claire! *opens it* All I get from this chick is forwards! I'm not going to "pass it on" and I'm not going to die..
This is a group of seedy people your friend hangs out with when he is not hanging out with you or your primary friend group. You wonder how your friend came to be acquainted with these people and how he could possibly enjoy their company. Oftentimes, your friend is admittedly embarrassed that he is associated with his Bridge Friends. Bridge Friends are generally shady people you don't want to be around.They are also typically slow, have terrible senses of humor, and often wear jean shorts. These are the type of people you would expect to hang out under a bridge.
Friend 1: "Where is Jerry?"
Friend 2: "He said he is going to some underground luau with his Bridge Friends."
Friend 3: "Those guys are creepy, I don't know why he hangs out with them."