American?????
Actually what we think of today as traditional Halloween customs (trick or treat, dressing up, jack o lanterns etc) originated in Scotland, not America.
The only part of it that is actually American is the use of pumpkins rather than the traditional turnip, as the pumpkin is native to North America and was introduced to Europe in the 1500s, but carving spooky faces into them didn't start until the mid 1800s, when people realised that they were a hell of a lot easier to carve than turnips which are very much harder and tougher, though in some parts of Scotland, people still carve turnips, which actually look spookier - their general colour and size makes them look a bit like shrunken heads, and because they are smaller, the candle inside tends to burn their lid, resulting in a distinct and memorable smell. This also makes then get very hot too, so many people carried them around on some sort of hook or chain, to avoid burning their hands.
Halloween itself is derived from the very ancient Celtic festival of Samhain, where it was believed that the veil between the real world and the spirit world was at its thinnest, allowing the ghosts of the dead to come over into the material world. Ancient peoples believed that some of these spirits had evil intent towards the living, and so they would disguise themselves as creepy demons/monsters etc to confuse the spirits into believing that they were already dead so they would leave them alone, which is where the practice of dressing up for Halloween comes from.
The practice of bobbing for apples is actually a seperate tradition which formed part of a ritual to determine the identity of a future spouse which has become part of Halloween for as long as most people can remember
Not sure quite how pulling apples out of wet vessels with your teeth is supposed to determine who you will spend your life with, but I'm sure there's a porn movie in there somewhere
