Warning: The following post contains Captain America: The Winter Solider spoilers (and maybe spoilers for a couple other things). Read at your own risk.
In Captain America: The Winter Soldier, we learn that the evil organization HYDRA has infiltrated S.H.I.E.L.D. in a vast, far-reaching conspiracy.
At one point in the film, Senator Stern (Garry Shandling) whispers, "Hail HYDRA" to S.H.I.E.L.D. Agent Sitwell (Maximiliano Hernández), and even World Security Council head Alexander Pierce (Robert Redford) says the words aloud.
Naturally, the internet has had some fun with this.