Phantump losing one eye as it evolves into Trevenant plays into the Norse Mythology motifs of XY - the event where Odin sacrifices his eye to gain more knowledge and effectively become wiser and stronger. This is supported by the line's secondary ability Frisk, which is similiar to Odin's all-seeing eye. Additionally, in some texts, Odin's mythical Gungnir is made from the wood of the World Tree.