Yeah, it's called a Chelsea Grin or Glasgow Smile. I know that, as does any 14 year old who would listen to Punk/Goth/New Wave.
Unfortunately for 70 years, Joker never did that to his victims. He has his Joker Venom, which is more insidious and downright evil. With a knife, it's pretty straight forward, and you can heal from it if he doesn't otherwise kill you. But Joker used his Venom in hundreds of different ways to snuff people with hideous, breathless pale uncontrolled death. If you got the antidote, you have a chance, but for the last 70 years, your pretty much gone when you start laughing.
Alot more evil than some lame gang related tagging of someones face.