Cottonmouth has Rattlesnake for Lunch
https://www.youtube.com/watch?v=U4j-3TIJALo
Crotalus bites the dust.
This happens to critters that have a brain the size of a sweet pea. A young Diamondback Rattlesnake gets way to close to a hungry water moccasin. Over the years I've watched this a few times and wondered how long that photographer had to sit still in a swamp in the middle of all those flies to get this video. The moccasin strikes Mr. rattler in the head then its all over except digestion.
There is a longer version you can watch if you wish that shows the whole feeding process. Just type in "cottonmouth eats rattlesnake" on you tube.