It can an also be extended to "eat shit, and then die" ESATD
Or if you mean serious business,
"Eat shit and then die, you dumb asshole." ESATDYDA
At which point it looks like a Mexican celebration phrase in ALL CAPS.
Person2: "Shut the fuck up, I am tired of your bullshit. ESAD"
"ESATDYDA ESATDYDA ESATDYDA ESATDYDA !!!!! AAAIIEE"
"what does that mean?"
"nothing it's just my new nickname for you"
"ESAD" said Sean
Carl then proceeds to eat shit and die.