The fad was created by a meme that pictured two guys on a rollercoaster doing the pose and yelling "ALIENS!" to the people below, using the speed of the ride to mimic his crazy hairstyle, but alienating can be used to interrupt the conversations of random strangers when a question is asked as well, answering with the obvious reason "ALIENS"!
Person A: "Yeah man, I don't even know where I could have left my keys."
Person B: "I don't get it dude, you are usually so organized with everything, but now you've been misplacing stuff all the time: your watch, wallet, phone, laptop, and now your keys?"
Person A: "I know, I know. I just don't understand why it keeps happening lately."
At this point, you decide to make your move and pick up speed to run past them to ensure a clean getaway so that you aren't left awkwardly standing there.
You (troll making the pose while running): "ALIENS!"
After you execute this maneuver:
Person A: "...Okay...what's with that guy?"
Person B: "Aw crap, we just got 'alienated'! I have to admit though, he got us good haha."
Person A: "A new trend, huh? I'm gonna look up this Alienating thing so I can use it on people."