Naglfar is the ship of the dead in Norse mythology, it is the largest ship in the world, and it is made entirely from the fingernails and toenails of the dead.
According to the poem Völuspá by Snorri Sturluson, The ship will be sailed by the jötunn Hrym and Loki from Muspelheim, and carry the army of the dead to the plains of Vigrid during Ragnarök. The sea level will rise as the ship gets closer to the battle with the gods.
From the east comes Hrym with shield held high;
In giant-wrath does the serpent writhe;
O’er the waves he twists, and the tawny eagle
Gnaws corpses screaming; Naglfar is loose.
O’er the sea from the north, there sails a ship
With the people of Hel, at the helm stands Loki;
After the wolf do wild men follow,
And with them, the brother of Byleist goes.
– Translation by Henry Adams Bellows