What is the most amount of money you've spent on ONE animal, at ONE time, at the vet? I'm not talking about an animal with a chronic condition that has to be seen once a month or something, but one stay at a clinic or hospital. I'm just curious.
Mine was $12,000. Two years ago one of my horses had to have emergency abdominal surgery. He had an enterolith blocking his colon. The surgery itself would've only been about $7,000, but his intestines shut down two days later and he was put into ICU, at about $1200 a day. (we also had to pay for the IV line, because he chewed through it). He had to be refluxed once an hour for 3 days. Finally things started moving the right direction again, and after over a week at the hospital, we were able to bring him home, where he had a 90 day stall rest, and he was a total lunatic by the time the 90 days were up. 
The vet told us later that with all the problems he had after surgery, his chances of survival were about 1%.
It's been over 2 years, and he's doing great. He's my show pony (he's half Arabian, half Welsh Pony), and was Half-Arabian halter champion last year.
None of my other vet bills even come close to that, and here's to hoping they never do.