Beaten to death by a flaccid penis. It would take forever, you'd probably dehydrate in the process, but you'd be mortified the whole time, that would be agonising.

Giving a medicine that makes you immortal for 1,000,000,000,000,000,000 years so then they can put you into the center of some giant star somewhere in the universe that has the most heat. The horrible thing is, the medicine that they give you, also has poisons that increase the sensitivity of pain to around 1,000,000,000,000,000,000%. This means that if you get touched by a dust spec, it would feel like getting shot 10,000 times or something. Imagine that, while in the center if the hottest star in the universe, getting burned, while not burning up, with no hope of even breathing any air, which would still hurt like hell because suffocation sucks, also with loads of regrets, sorrows and a general, unfulfilled life, but then in about waiting half of the time of your immortality, they will take you out of the star- whilst sandpapering, beating, cutting and tormenting you on the way- so they can take you into the "antimatter dimension" where you will blow up in destructive, cataclysmic, big-bang-like explosions- since you are a piece of matter- and matter doesn't go well with antimatter. It will hurt way worse than the star, and you will blow up billions of times. Eventually, you will be the most depressed living thing in existence. After years of pain, you would of already drifted away from the millions of antimatter explosions, and you would some how reach within the deepest, unknown parts of the universe, drifting in space, with no air, whatsoever, suffering out the last and final day of immortality, to be sent into the warm, loving embrace of death... Oh wait, no... they dosed you again! :D. But this time, it's 1,000,000,000,000,000,000 years x1,000,000,000,000,000,000 years with infinite pain sensitivity! You seriously would be depressed. :D

I'd also say that, being slowly sand-papered from the extremities inwards, being left long enough for your wounds to seal, then starting on another body-part, until dead.

there are many worst possiblilties to die. If any of you watch 1000 ways to die you will know what I mean

Boredom. Just being stuck in a small room with nothing to do (even if you had basic food and water). I am personally quite scared at the thought of being bored and just sitting there would be the worst death ever (as you would die eventually).

With regrets.

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Getting dumped into the bottom of the Mariana Trench, inside a dodgy submarine that would fail apart exactly when it reaches the bottom. (The water is soo deep that each inch weighs tonnes.) Not to mention the fact that it is so deep you can put Mount Everest inside it, and it would still be under about a mile of water and it is impossibly dark! Scary O.o

Crucifixion is the worst way to die .

by being attacked with an angela untill you cant breathe and she beats you up with a fork in the forest!

To be set on fire. The pain is excruciating and it drives a person screaming into a frenzy.