Jack in Irons (also spelled "Jack-in-Iron") is a mythical giant of Yorkshire lore who haunts lonely roads. He is covered with chains and wears the heads of his victims. He wields a large, spiked club.
His name may not be Jack as other Yorkshire folklore refers to "Jack-of-Green" and more so the name "Jack" may just be a term for calling the person an unknown male, like John Doe today.
Jack in Irons is a monstrous giant or ogre who haunts roads in Yorkshire legend, despite this he is often given ghostly or demonic attributes and was greatly feared due to both his hideous appearance and sadistic personality - he may well of been a type of "ghost giant", since many of his abilities seem to be that of an undead.
Though victims certainly still felt the physical presence of the monster in the form of his large spiked club, his favored means to kill a victim and collect their head, which he would then keep as a trophy.
The exact origins of the monster is unclear but like many similar beings in folklore he is likely a combination of traditional bogeyman figures and a symbolism for the fears many had of lonely roads and night travel - where people ran risk from attacks from wild animals or bandits, as well as the unpredictable elements.
As a giant, Jack In Irons possesses immense strength, durability and a tendency towards great physical violence - he is said to favor the use of a large, heavy club with spikes on it by which to bludgeon victims to death and is covered in equally heavy chains so as to have plenty of room to display the heads of those he kills.
Like many giants, Jack In Irons has limited intelligence but may also display (dependent on the tale) more supernatural powers, as giants in folklore are usually elementals or rogue spirits of the wild.
- Despite being called a giant, Jack in Irons has more in common with an Ogre - due to his exceptionally violent and ugly appearance.