Thank the heavens for Wikipedia, without which we may all have remained ignorant of Spring Heeled Jack:

Spring Heeled Jack was described by his victims as having a terrifying and frightful appearance, with diabolical physiognomy that included clawed hands and protuberant red eyes, which "glowed like fire". One of these victims also recounted that, beneath a black cloak, he wore a helmet and a tight fitting white garment like an "oilskin". Many depositions also mention a "Devil-like" aspect, wearing a tight fitting oilskin outfit, although its colour alternated between white (the most frequent) and jet black. Many a witness stated that Spring Heeled Jack's physique was athletic and sturdy and that he was capable of effecting great leaps. Several reports mention that he could breathe blue and white flames from his mouth, and that he wore sharp metallic claws at his fingertips. At least two testimonies denote that he was able to speak in comprehensible English, albeit with an uncommonly deep voice.

Eons ago I remember reading in our local paper about a farmer who had an "encounter" with a similar creature after a bad storm blew apart his barn. It must have been a practical joke story (this was the Dumas Clarion after all), but the story scared the bejeebus out of me for years after.

Fweaky...