Or else you will DIE! (also known under the derivative You must die!) is a one liner quoted by Ganon in The Philips CD-i games Link: The Faces of Evil and Zelda: Wand of Gamelon. Alongside the other various cutscenes in the two games, the cutscene featuring the quote is among the most notably (in)famous for its poor voice acting and animation, became subject to comedic ridicule, and is commonly utilized as a source for YouTube Poop and YTPMV's.

Origin

Nearing the end of the Legend of Zelda CD-i game Zelda: The Wand of Gamelon, a cutscene takes place where Ganon shouts in anger at Zelda:
"You dare bring light to my lair? You must die!"

In another of the Legend of Zelda CD-i games, Link: The Faces of Evil, Ganon says the following during the cutscene preceding the final boss battle:
"Join me, Link, and I will make your face the greatest in Koridai! Or else you will die!"

Videos

The videos below show the original phrases.

"You must die!"

"Or else you will die!"

Derivatives

The two phrases (mainly the second one) have become very common audio and sometimes video clips in YouTube Poop, YTPMVs and other parodies on Youtube, especially clips of "DIE!"
Below are some of the many videos on YouTube featuring this clip:

While the original, unaltered audio is hard to find, it is virtually impossible to watch a series of YouTube Poops without hearing it at some point.