Everything that reflects in Nidhogg's eyes is a potential meal. All life is nothing but food for Nidhogg. Its one fear it is that its feast will eventually come to an end.
In Norse mythology, Níðhöggr (Malice Striker, often anglicized to Nidhogg) is a dragon who gnaws at a root of the World Tree, Yggdrasill. In the mythology, the Nidhogg is said to be controlled by only one person, the Norse goddess named Hel.