I've discovered this incredible bug that creates potions that actually kill you while on creative mode. You need MCEdit and Sethbling's modifypotions filter to recreate it, or you can download the world with the potion here: http://www.mediafire...2xjd7itz4iza1h9
The potion is Instant Health level 127 (potion.potency.126) and it is set to last for 1,000,000 seconds.
This is what it does: Splash yourself = instant death, even on creative Splash undead mobs = about as much damage as a punch Splash regular mobs = They will suddenly despawn without any death animation, and without any drops.
Not sure how this could be helpful, but it's a really fun bug.
It shouldn't matter, but I was using the 13w09a snapshot.
Any effect outside of those provided in vanilla circumstances should be considered unsupported officially and may or may not work as you'd expect.
As for causing chaos on servers, that is up to the how the server works. If players are able to have access to such items which cannot be obtained normally, then it would be on the server owners hands, not Mojangs.
EDIT: Darn, responded to a necro'd thread. Well, info sharing is there regardless.
The Meaning of Life, the Universe, and Everything.
This sounds a lot like something to be used in a type of map or something. Personally, I would have a lot of fun playing around with this 'insta death' or 'vortex' potion in battle or some sort of pvp/pve map.