The Hørdum Stone is a Viking painting stone discovered in Hørdum, Tystede, in the northern Denmark region, which depicts a legend from Scandinavian mythology involving the god Thor and the serpent Jörmungandr, also known as the Midgard Serpent.
The Hørdum Stone was found in 1954 during trenching work next to the church in Hørdum. Before the historical significance of rune and picture stones was understood, they were often repurposed as construction materials for roads, bridges, walls, and buildings. The image on the stone illustrates a legend recorded in Hymiskviða in the Poetic Edda, in which the Scandinavian god Thor goes fishing for Jörmungandr, the serpent of Midgard. Thor's fishing expedition involves Jotun Hymir, and they use a bull's head as bait. In the course of the story, Thor hooks Jörmungandr, but the serpent either breaks free or, according to the Prose Edda's Gylfaginning, the line is severed by Hymir.
The image on the Hørdum Stone depicts Hymir, Thor, his fishing line, and a portion of the serpent. It notably shows Thor's leg piercing the hull of the boat, which aligns with the version of the myth presented in Gylfaginning. While the image of the bull's head bait is not present on the stone, it may have been part of the image but has worn away over time. Hymir is depicted with a tool, seemingly preparing to cut the fishing line, consistent with the Gylfaginning version of the myth. Some scholars have suggested that the image of the serpent's head can be discerned on the edges of a natural crack in the rock under the boat.
This encounter between Thor and Jörmungandr appears to have been a popular motif in Scandinavian art. Other stones with images related to this myth include the stone with images of Ardre VIII, the Runestone of Altun, and the Gosforth Cross. A stone slab, possibly part of the second cross at Gosforth, also depicts a fishing scene with a bull's head as bait.
The Hørdum Stone is currently displayed in the church in Hørdum, where it stands as a testament to this iconic Norse mythological encounter.