The French champions took a cheeky swipe at Costa ahead of their Champions League last 16, second leg clash with Chelsea at Stamford Bridge tomorrow night.
Costa, who has only scored one goal in 14 Champions League appearances for the Blues, is currently wearing a mask after breaking his nose in a training-ground accident
And PSG poked fun at him by tweeting a Vine just before 3pm on the club account with the message: “Have you found the hero? Now find the imposter!”
The accompanying video flicks through various masked heroes and villains, including Batman, Darth Vader, Iron Man, Zorro and Kylo Ren, with a strapline: “Spot the fraud” across the bottom.
Costa is expected to start against PSG despite missing Chelsea’s draw with Stoke because of a minor tendon problem.
The Spain international, who was linked with a move to the French giants this week, could be key to the Blues overturning a 2-1 deficit in the tie.
But his only goal for Chelsea in the Champions League came in September’s thrashing of minnows Maccabi Tel Aviv in the group stage.
PSG had earlier tweeted a similar video asking fans to "find the hero" - Brazilian defender Thiago Silva.