WARNING!!!! PAGE MAY CONTAIN SPOILERS FOR THE GAME "UNDERTALE"!!! READ AT YOUR OWN RISK!!!
Undyne (/ˈʌn.daɪn/, UN-dyne) is a fish-like monster that leads the Royal Guard. Clad in her full armor, she pursues the protagonist through the entirety of Waterfall, frequently evaded or inadvertently thwarted by the Monster Kid.