We've seen stars photobomb people before, but one's up there with the best.
Robert Downey, Jr., realizing that a fan recognized him and was about to take a photo on the sly, turned the tables on her in one seriously Iron Man photobomb effort:
The girl was totally doing the whole, "Oh, I'll pretend to take a selfie so I can really get a photo of him with the reverse camera and half of my face cut off" move.
This is Iron Man, though. He is aware of your secret plan. Very well aware of it.
Just as she was about to put her scheme into action, the 49-year-old star, briefcase in hand, graced her selfie with a fist pump and a very cheesy expression.
She posted it online, and Downey clearly got a kick out of his antics as well.
The actor decided to post the image on his Facebook account, along with the caption: "You're never too old, busy, or famous for a good photobomb."
Words to live by, and ones these celebrity photobomb pros also heed: