Frost Serpent

The Frost Serpent is an Emblem Heartless that appears in Kingdom Hearts III.

Kingdom Hearts III
After being expelled from the top of the mountain by Larxene's gust of wind, Sora, Donald, and Goofy soon find themselves trying to out-sled an avalanche coming after them. Three Frost Serpents chase after them and are destroyed. New Frost Serpents then appear, knocking the heroes down the mountain.

Location
The Frost Serpent can be found in Arendelle in The North Mountain/Frozen Wall area. The quickest access route would be to warp to The North Mountain/ Mountain Ridge save point where Elsa's Ice castle is. Go through the hole in the wall and it will lead you to the top of the Frozen Wall. Follow the path a bit around the turns and there will be a cutoff where Sora can go into a swan dive and 3 will spawn when you land.

Unlike Kingdom Hearts II, you only need to leave the area and return to it for the Heartless to respawn compared to Kingdom Hearts II where you had to move up to three rooms over in total to respawn an area.

Design
The design was slightly based off of the Storm Rider from the Land of Dragons in Kingdom Hearts 2.