WARNING: There are parts of this post that are quite graphical. Since nature isn't always pretty I have decided to include a photo that may gross out some people. I am giving you this warning so that if you are squeamish you can decide whether or not you would like to continue.
Dragonflies are predators. They hunt, kill and eat other insects. Unfortunately when you are an insect sometimes the predator can become the prey. All sorts of other creatures often snack on dragonflies. This includes birds, frogs, spiders, wasps and more.
Dragonflies, also often attack and eat other dragonflies. Typically it is the largest dragons that eat the smaller ones. One day while I was out photographing dragonflies at Wild River State Park during the summer I had the opportunity to photograph the life and death struggle between two dragons.
In this case the larger yellow dragon appeared to be a midland clubtail while the smaller one looked like a rapids clubtail. The midland grabbed the rapids by the thorax, most likely coming at it from above, wrapping its legs around the smaller dragon in a death grip. Then its used its jaws to eat out the thorax of the rapids. The rapids club put up a fight. Its attempt to break free flipped the pair over on their backs but it could not break the grip of the larger dragon. I don't think that the midland was quite finished with its meal but it decided to use caution around the large predator that was taking photos. As you can see from the last photo there was not much left of the rapids clubs thorax. Perhaps the midland returned later after I left to finish its meal otherwise I am sure that scavengers like ants, bees, or spiders finished the job.