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.
- 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.
- In some Bloom County strips, Playful Hacker Oliver Wendell Jones sometimes wore a pirate costume and talked like one while illegally hacking.
- 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.
- 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.
- When the hacker group in Who Am I hacks the German stock market, they show the DAX's daily curve in form of the finger which causes some irritation in the commentator.
- In Cory Doctorow's short story "Unauthorized Bread", when Salima downloads a hack into her smart toaster (because the company has gone bust, leaving the toaster unable to identify if the bread in it is from an approved source, and therefore assuming it isn't and refusing to toast it), the loading screen shows a 3D skull eating toast.
- 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.
- In Saints Row IV, after freeing Matt Miller from his Simulation and going to rescue him from the Zin mothership in the real world, you'll find that he's not only managed to hack open several doors all on his own, but he's also taken the time to upload a .gif of a laughing Decker skull to their control panels as well.
- In Overwatch, a skull without crossbones, stylized like a calavera, is the symbol for Sombra's Hack ability in her hotbar, and marks anything she's used it on. It also shows up when she hacks the Play of the Game screen and seems to be her personal Sigil Spam.
- In Watch_Dogs 2, DedSec uses the Grim Reaper as their personal logo and their equivalent of Guy Fawkes masks are LED skull masks.
- In Splatoon 2: Octo Expansion, Marina's personal insignia is a stylized octopus with a pair of headphones. Whenever she hacks into Kamabo Co.'s systems, a pixelated version of it appears on the screen.
- 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."
- 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 persists there.
- YouTube has a few videos with virus pranks. One of them involves a skull animation.
- The rather infamous (and highly dangerous) Petya malware features this, it replaces the boot sector upon infection.
- During the late eighties and early nineties there was a prank software in one of the volumes of the "Fish Disk" (a series of various freewares distributed by magazines) called "Skull" which stays idle but in set time will turn the whole screen to image of skull.