User blog comment:Kogath/Monster Hunter XX Discussion/@comment-6050823-20161208071926/@comment-6050823-20161208162923

The water vapor from Heavenly Eye Mizutsune's eyes actually do make sense, well in a way. Under a Mizutsune's eyes are glands, called the Bubblefoam Sac (Japanese 泡液ぶくろ), that allows it to breath the bubble secretions from its mouth. The developers of Monster Hunter series describe it to be like inflating bubble gum on your tongue.