！
You're scum!
Literal
You [topic-は] scum is!
A curt, blunt insult. お前 is the rough masculine 'you,' confrontational in most contexts. クズ (written in katakana for emphasis; also 屑 in kanji) literally 'scraps, waste,' used as a general-purpose insult for a worthless, despicable person. The sentence is the minimal topic-copula structure (は...だ), maximally compact for maximum impact.