[Dujon] That is possibly the most traumatic thing I have ever heard. Thank God that disgusting item didn't land IN YOUR HAIR. However, I was under the impression that the things that paralyse spiders and lay their eggs on them so that they get slowly devoured by grubs are not wasps but ichneumons, which look similar. Ordinary wasps, however, do carry body parts in the way you describe - I once watched a wasp attacking a bee, which it did by sitting on its back and systematically chewing through its thorax. When it finished it flew off with the abdomen - presumably the yummy bit - leaving the front half of the bee staggering around until I mercifully squashed it. Perhaps what you saw was the aftermath of a similar act of piracy. The mere existence of the ichneumon, by the way, was partly responsible for the Victorian "crisis of faith", because many found its existence impossibly to square with the notion of a good creator God. Incidentally, I will keep your anecdote for when I need to terrify my girlfriend. She refused to come to bed last night because a SMALL MOTH was sitting on the wall. Well, that's what she said anyway...
[Spiders] I see your spiders (*shudder*), and raise you The Japanese Spider Crab: The biggest crab is the Japanese Spider crab (Macrocheira kaempferi), which lives on the floor of the north Pacific Ocean; it has a 12 ft (3.7 m) leg span.