Níðhöggr
Níðhöggr ('Malice-Striker') is the monstrous dragon in Norse mythology gnawing Yggdrasil's roots in Niflheim. Wingless, serpentine, dark-scaled, red-eyed, powerful jaws. Creates decay and corruption; awaits Ragnarök to consume all. In Vafþrúðnismál 37 and Gylfaginning 18, Hræsvelgr (eagle-guise jötunn) creates wind; Níðhöggr gnaws roots.