A magnifying glass (or, in this case, thick glasses) can be used to create a fire. This is done by positioning the glass so that the sun's rays are focused by the lens on a small point on a pile of dry kindling.
When you skewer the carcass of an animal like a pig, you run the split through it and out its mouth. The pig needs to be supported for its full length, or else it may fall apart when it gets tender. If you want to spread the pig flat, you will have to split the backbone of the rib cage from the body cavity side.
When summoned by witches or sorcerers the devil, or Beelzebub, was said to appear in the form of a fly, and thus was known as "The Lord of the Flies."
He may also have got this name as flies were once believed to be generated in the flesh of corpses.