In the play Julius Caesar by William Shakespeare, there are several ironic incidents surrounding Cassius' death.
First, Cassius is killed on his own birthday. Second, he is killed with his own sword. The sword happened to be the exact same sword he used to kill Julius Caesar. Third, he tells his servant to kill him because he thinks that Brutus' army has been defeated and Brutus has been captured. However, that's not the case. The message is relayed incorrectly. While Cassius believes he is next to be imprisoned and killed, we, the reader, know he is mistaken. Under this mistaken premise, Cassius gives his sword to his servant and his servant stabs him and kills him.
In the end Cassius says,
Caesar, thou art revenged,
Even with this sword that kill'd thee.
For more information about the play Julius Caesar, see