Floob
When two people are walking toward each other in a hallway, stairwell, etc., and the two both attempt to pass one another one the same side.  Most often results in an awkward repetitious series of movements where both persons attempt to rectify the situation by quickly choosing the opposite side, only to find that the other person is mirroring their movement. Can sometimes lead to a collision but more commonly a less than enthusiastic utterance of some polite phrase such as "excuse me" or "sorry."
"I just floobed some chick in the alley;  it was weird."