Craziest bugs ever?

[migo]

Oblivion has (had?) this bug where if you sit in a certain chair, you're unable to complete a quest. Modern Warfare 2 has one that unlocks 5 SNK arcade games. What are some other games with bugs that have unexpected results that just don't make any sense?

 

[The Amazing Tea Alligator]

I still hold the spycrab to be the best glitch ever.

 

[Irridium]

The flying Bird men and Donkey women in Red Dead Redemption.

I'm so glad I didn't patch the game.

 

[TheNamlessGuy]

DELETED

 

[ShasoRmyr]

There was an article in a recent game informer about some strange bugs. My favorite that I've heard about was in scribblenauts where if you spawned 2 rabbits they would spawn other rabbits and this would continue until the game crashed.
Edit: A few more amusing ones here.
http://gameinformer.com/b/news/archive/2009/10/05/news_2F00_scribblenautstidbits.aspx

 

[silver wolf009]

I still hold the spycrab to be the best glitch ever.

I love spawning hundred of bots with programing to simultanious spycrab. It awesome.

OT: Related to TF2, im rather fond of the sniper hump although im not sure if thats a glitch.
Fallout 3 had the invincable fawkes glitch for a while which let him take the orbital strike that downed Liberty Prime. That got a laugh out of me.

Other than that, The glitch i stumbled upon at random in Halo 3's forge, You would lose your arms, flicker into pure invisbility, not camo, and when you were killed your body would fly very slowly to the right of the map, lagging up the game as it went, hit the wall and crumple into the size of an atom before your eyes.

 

[The Amazing Tea Alligator]

OT: Related to TF2, im rather fond of the sniper hump although im not sure if thats a glitch.

Absolutely.
And don't forget...

 

[Zap Rowsdower]

I was reading about a bug in oblivion in which they were testing the lifelikeness of NPC's. There was a quest invoving a prisoner that you could not complete because after a while the guards got hungry and ate him.