"You should try uploading a virus to the mainframe. I find viruses that feature a laughing skull work the best."Whenever a character, be it the Asian and Nerdy hero or the computer genius villain, decides to hack into the opponent's computer and mess up with his plans, he'll never stop at just making the computer malfunction. You've got to do it with style. And so, a Skull and Crossbones image shall take the entire screen of the hacked computer, possibly followed by the voice of the hacker laughing in the background. Alternatively, an 8-bit image of the character doing the hacking, or his logo, or perhaps a mix of the above, shall appear on the screen, such as a Skull and Crossbones, only the skull is wearing the very same hat the hacker wears. Reactions vary from confusion to aneurysms. Named after the fact that Skull and Crossbones happen to be the Pirate's symbol of choice. Note that the trope is rarely, if ever, performed by an actual pirate, since they usually try not to be noticed.
— Dexter Grif, Red vs. Blue
- In V for Vendetta, V has actually been manipulating the Fate computer for years. The "pirate flag" is just the final stroke to drive the Leader completely over the edge.
- One Batman storyline has Batman investigating a criminal / terrorist dressed in a mask and he finds a video file of said masked man...who removes his mask to reveal a pixellated skull.
- A Thin Veneer: Commodore Acaltha's trap in the Berlin system includes an Electronic Warfare attack the Minbari garrison force, complete with suddenly-blacked-out-then-returned computer displays being overrun with laughing skull-and-crossbones.
- Independence Day is the Trope Codifier, when David displays a laughing skull and crossbones to the aliens as a joke... just before he and Capt. Hiller throw a nuke at them. Played with in that David didn't display the skull until long after he'd covertly hacked into their system and uploaded a virus: he only did the skull thing when the jig was up and stealth was no longer an option.
- Happens like that in Tanguy when the title character's father sends a virus to his PC. The words "I Love You" (name of a notorious virus back then) flash on the computer screen along with a skull.
- All over the place in Hackers. The viruses launched by the hackers all have some malicious and/or cute animation that's displayed while they're mucking about in the system.
- Skyfall: Silva does this with a stylized skull and "God save the Queen" playing in the message.
- In Geist, ghost Raimi can possess a computer and cause it to flash the skull-and-crossbones, pretending to be a virus to scare a technician.
- The Jawbone virus in the Purple Moon computer games. Expanded Universe material goes out of its way to say that this is the only thing it does, as while invading the computer of the local equivalent of Bill Gates is not beyond Bo, doing actual harm is.
- As they browse the Deep Web, the protagonist of Welcome To The Game is constantly hacked. Each hacking minigame starts with a cackling skull.
- Invoked in Red vs. Blue: Reconstruction. As Simmons tries to hack Command's computer system, Grif unhelpfully offers advice such as, "You should try uploading a virus to the mainframe. I find viruses that feature a laughing skull work the best."
- The Archer episode Tragical History features a computer virus accompanied by a cute pirate video and an Ear Worm.
- Such practices of depicting hackers using fancy graphics/logos to identify themselves most likely originated with software pirate groups way back in the 80's - who typically did have some form of ASCII based logo that they would insert into the game they cracked and released. Even today, it's common to find such logos/art in the .nfo file that often accompanies such pirated software. With Hollywood being Hollywood, it's no surprise that they have no concept of the difference between a computer cracker and a software pirate.
- Early viruses were usually just made by savvy kids pulling pranks. They'd often have the virus interact with the user for fun. Nowadays, viruses are a way to steal money, and their creators don't want them to be noticed. See here.
- Website defacement being a purposefully showy practice, this kind of calling card subsists there.
- YouTube has a few videos with virus pranks. One of them involves a skull animation.