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.
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.
- Jack in Irons, despite being called a giant, has more in common with an Ogre - due to his exceptionally violent and ugly appearance.