I was browsing Reddit this morning, as I always do; and came across this bad boy in one links comments.
The Tarantula Wasp is horrific in it's treatment of Tarantulas, I am not saying that I am a fan of the hairy eight legged insects - but I certainly feel pity for them. You see, our giant wasp friend here -- as their name suggests -- hunts down Tarantulas... alive.
It doesn't hunt them with the intention of eating their prey - oh no. It will fight, and sting a Tarantula with its 1/3 inch stinger and deliver what has been described as the worlds second most painful insect sting. The venom from this subsequently paralyses the victim, allowing the wasp to drag its living body to to either its own burrow or a specially created wasp nest.
Here is the really cruel part: the wasp will then lay an egg into the living victim and seal it in to it's excruciating doom. The egg inside the spiders abdomen will then hatch, and the larvae will begin to feed on the spider from the inside out. It will actually avoid vital organs to keep the vicitim alive for as long as possible before emerging for the abdoment several weeks later to begin the cycle again.
Here is a video of our sadistic killer in action!