I don't know if it was the worst, but it was one of them. The day before I was combining some oats over about a mile from my Uncle's house with the old John Deere combine. I was roading it home afterwards and saw his Angus Bull, feet-in-the-air-dead over in the adjacent pasture, several hundred yards from Uncle's house. I put up the combine and went home. Next day, I roaded the Case 930 over to put up Uncle's blade that I'd borrowed to blade the driveway to Dad's house. I was probably early twenties and this was probably 1982 or so. So I drop the blade off behind Uncle's defunct hog house in a lot where a bunch of equipment was. I smelled this awful stench. It even made me light-headed. I looked on the ground and there was this trail of black fluid. Didn't really look like blood. I followed it over a little ways in the lot and there was the bull, all bloated up. I have a very strong fluid but I was about sick. I went over and went to put the top arm of the three-point in its hanger which was spring steel and needed a pretty good push to get it in. I slammed my finger in it and it hurt like hell. I got on home and was about half sick from the pain and I guess, the stench. My fingernail went black and a few days later I had to heat a needle up and stick it in the nail to drain the black blood out. Fingernail peeled off after much pain and when it grew back didn't look right. It still looks effed up and reminds me of that day.
Later I told my Uncle about it and asked what killed his bull. He said he didn't know but it had been mutilated. No blood around it, just the weird fluid that didn't really look like blood. Stench that was worse than any dead animal. Surgical precision genital removal, tail removal and strip between the ears and ears removed. Neighbor said it was a Satanic cult. Weird how my Uncle and Aunt never heard anything even though their house wasn't far away.
