Here you can see an ant shooting a dose of venom straight into a centipede's head. The centipede is translucent, so you can actually see the stinger in its brain. And there's more.
Alex Wild, who took these photographs, is a scientist who researches ants. He also happens to be an extremely talented photographer who always manages to capture both the danger and the beauty of the insect world. While he has a number of gorgeous ant portraits, I think his most stunning work comes in action photos like these, where ants are battling it out with other insects. That ant stinging the centipede, by the way, isn't killing the centipede. She's just paralyzing it so that the larvae in her hive can munch on it while it's still really fresh.
Here you can see a very strange encounter between a fly and an ant that was wandering up a tree. Wild says he saw flies landing on the ants, holding them against the tree for a few seconds, and then flying away. He couldn't figure out what was going on until he used the magnifying action of his camera lens to get a good look at what the bugs were doing. It turned out the flies were mugging the ants, pinning them down and stealing their food.
Most flies take their attacks on ants far beyond mugging, however. These flies use ants as incubators for their larvae, using a canulated organ called an ovipositor to inject eggs into the ant's abdomen. Eventually the baby flies eat their way out of the ant's body, getting a lot of nourishment but killing the insect in the process. In this photo, you can see the fly injecting her eggs into the ant.
If you want to see more of Wild's exceptionally cool insect photography, including some friendly pictures that do not involve muggings or deadly injections, check out his blog Photo Synthesis.