If you eat something really delicious, do you say, "This is so delicious that I could die"?
so "adjective" that "someone" could die
Does this sound like slang?
I would call it a kind of hyperbole.
I wouldn't call it slang.
figure (or figure of speech)an expression that departs from the accepted literal sense or from the normal order of words, or in which an emphasis is produced by patterns of sound.
Scroll down to read more: http://www.answers.com/topic/figure