Nightwing VS Daredevil (DC VS Marvel) - S5-E12
Nightwing: Hah, see you in Hell. (00:17:40)
Nightwing VS Daredevil (DC VS Marvel) - S5-E12
Daredevil: I wish I could see the look on your face.
Nightwing: Me too. (00:17:15)
Nightwing VS Daredevil (DC VS Marvel) - S5-E12
Nightwing: What are you?
Daredevil: Better. (00:16:10)
Samurai Jack VS Afro Samurai - S5-E9
Continuity mistake: After jumping right behind Jack, Afro attempts to stab him, and Jack avoids it. When Jack turns back to face Afro, it looks like there is a bit of distance between them, despite Afro being right behind Jack in the exact previous shot.
Trivia: This was the first episode of the show with actual voice acting.