Julius Caesar's last words when being stabbed to death, according to Shakespeare (2,2,5)
I believe the answer is:
et tu brute
(Other definitions for et tu brute that I've seen before include "Caesar's reported words on being stabbed" , "Julius Caesar's last words to unexpected assassin" , "According to the Bard, Caesar's final words" , "Famous last words" , "Julius Caesar's supposed last words" .)