Gullinborsti is a giant boar that is used to drive the chariots of the Norse god Freyr. It name means ‘The One with the Golden Bristles’ the Gullinborsti can run faster in the air and across the water then a horse both day and night can easily run through the night with golden bristles that shine so bright. From the almost metallic description that Snorri Sturluson gives of Gullinborsti gives of Gullinborsti in Gylfaginning that the boar is also called Slidrugtanni, is actually a kind of mechanical automation. This idea is reinforced by the fact that Gullinborsti was made by the blacksmith dwarf Brokkr whose implies ‘one who works with metal fragments’.
John and Caitlin Matthews, The Element Encyclopaedia of Magical Creatures, 2013, Gullinborsti, p 218