Saw this weird bloke when I was on a walk today...
The Spider Wasp
Spider wasps are often seen digging in soft sandy soil, dragging huntsman spiders along. Some species are known to bite off the legs of large hairy spiders, trimming them to make them easier to handle. Others have scales that help them walk on spiders' webs, allowing them to sneak up and attack the owner.
The spider wasps you are most likely to see and hear are female wasps preparing nest chambers for their larvae. They dig a burrow using long spines on their front legs, then search rapidly around tree trunks and on the ground for a spider. On finding the spider, which may be as large as a huntsman or funnel-web and twice as heavy as itself, the wasp stings and paralyses it, and then drags or flies it back to the burrow. She then lays an egg on the spider's body, and seals it in a chamber or cell at the end of the burrow. The larva hatches and feeds on the body of the spider before pupating in a thin silky cocoon in the cell.
Some spider wasps sting the spider and lay an egg on it but do not dig a burrow to put it in. The spider is left where it was stung and the larva hatches and eats the spider. A small number of Spider Wasps steal spiders from other Spider Wasps for their own larva. This behaviour is known as klepto-parasitism (klepto: Ancient Greek for 'theft').