According to legend Spring Heeled Jack only appears at night abducting people, though he abducts women most of the time.
He is a feared demon who causes the disapearance of many; It's unknown what happens to his victims.
Spring Heeled Jack is said to look like a mustached gentleman wearing a suit, shoes, tie, gloves, top hat, and a monicle.
Spring Heeled Jack is said to jump very high and that he can leap through great distaces which gives him the appearance of flight.
(hence the name Spring Heeled Jack)
It is believed that he has super jumping abilities, others claim that his shoes have springs.
It is also belived that salt is his weakness, it is said that salt can turn him into stone.
In the legend, water can restore Jack from being a stone statue.
After reading this, I realized how incorrect much of the information was (there were also many spelling mistakes). Granted, this is the 'Urban dictionary', but it was interesting to read about their version of this historical figure. The mention of abduction was interesting. In all of the sources I have looked at, none of them ever mentioned abductions. In fact none of the victims were ever killed during an 'actual' attack (ones that died, often did days later due to shock). It was also fun to hear that salt can turn him into stone. I am really curious as to where this information came from!
If anyone is interested, Urban Dictionary has a variety of Spring Heeled Jack merchandise with their lovely definition printed on t-shirts, mugs, magnets, and stickers!