http://en.wikipedia.org/wiki/Irukandji_syndrome
Choice quotes:
> most cases require intravenous opioid analgesia ...
and
> One unusual symptom associated with the syndrome is a feeling of "impending doom".[13] Patients have been reported as being so certain they are going to die, they beg their doctors to kill them to get it over with.
1.8 Bullhorn acacia ant: A rare, piercing, elevated sort of pain. Someone has fired a staple into your cheek.
[1] http://scienceblogs.com/retrospectacle/2007/05/16/schmidt-pa...
(from the comments which have no shortage of bug bite stories...) "The guy should have let one bug sting him on the back of each hand, then see which hand grabbed the other in pain. That way he could compare them semi-directly, sort of like the rock hardness scratch tests. That’d involve a lot of extra stings, but it’s for a good cause..."
> On the television program Super Animal, a woman compared her pain from childbirth to her experience with Irukandji syndrome: "It's like when you're in labor, having a baby, and you've reached the peak of a contraction—that absolute peak—and you feel like you just can't do it anymore. That's the minimum that [Irukandji] pain is at, and it just builds from there."