Creature Feature Friday: Spring-heeled Jack, the Terror of London

On a recent member episode, Episode 380: Gateway Into a Paranormal Life (Members), guest Sean described seeing an entity wearing a cloak that “folded in” on itself and disappeared before his eyes. He described the strange being as looking like Spring-heeled Jack, the Terror of London - a figure straight out of folklore but nonetheless real to the people he allegedly terrorized. Who, or what, is Spring Heeled Jack?