A posteriori

Hotspur: O, I could prophesy,
But that the earthy and cold hand of death
Lies on my tongue. No, Percy, thou art dust,
And food for --
Prince Hal: For worms, brave Percy. (1 Henry IV, 5.4)

Aposiopesis is a wonderful and flexible technique for showing a character's overcharged emotions. Hamlet makes use of aposiopesis to illustrate his grief and shock at his mother's behavior after the king's death. One example is when he can't finish his comparison between his mother and Niobe: "Like Niobe, all tears--why, she, even she-- / O God! a beast that wants discourse of reason / Would have mourned longer." Shakespeare again makes use of the technique when King Lear rages against his evil daughters. Shakespeare makes him so upset he can't even think of a proper punishment for them as the old king breaks down in blustering tears: