Mortacci tua

Romanesco dialect

1st
It literally means: "your despicable dead relatives".
tua="your", singular

mortacci="despicable dead relatives"
It's used to express strong disapproval of someone (or something that somebody did)

variations :

"mortacci mia"=" my despicable dead relatives"
"mortacci sua"=" his/her despicable dead relatives"
"mortacci vostri"=" your despicable dead relatives", plural

2nd
Sometimes used like an element of surprise

1st
Someone punches you: "Mortacci tua! What the fuck are you doing?"
A group of people pull a prank on you: "Mortacci vostri! You guys are assholes"
2nd
-"Have you heard? He bought a new super-car!"
-"Mortacci sua!"