Suddenly SHOUTING!

Film — Animated
Ruber: Then it's time for the new king and I vote for me. Sir Lionel: I will not serve a false king. Ruber: Then serve... A DEAD ONE! When learning that Excalibur is lost in the forbidden forest: Ruber: The Forbidden Forest. Griffin: Precisely, master. Ruber: Have I told you today, how magnificently and totally worth-LESS YOU ARE?!! Also, when cornering Kayley in the courtyard where the stone was during the final battle: Ruber: You're in the way, just like your father! Since you're dying... to BE LIKE HIM! Let's see if I CAN HELP YOU OUT!!
 * In Quest for Camelot: Ruber is prone to these.
 * Before he goes into a violent rage in a meeting with the knights of the round table:

Western Animation
"No one would ever suspect Mother Nature to harbor a spring loaded circus cannon and BLOW INNOCENT BYSTANDERS TO KINGDOM COME!   "Hey, Jonny. People really like it when you say WHY ALL THE TIME! Tallest Red: (After hearing Zim Motor Mouth for three hours) I was curious to see if you'd shut up on your own, but it's been three hours now, Zim. THREE HOURS!
 * Edd from Ed, Edd n Eddy has a knack for doing this when exasperated.
 * Eddy tends to do this a lot, too, more or less as a side-effect of his lack of an indoor voice.
 * Happens surprisingly often in Invader Zim, most by the titular character, but other characters are prone to it.