The Watcher is an enemy in Mother, found in Magicant and its underground area. This enemy only attacks, and performs no other actions. Watcher will either appear by itself, or in a trio alongside one Momseyes and one Dadseyes.
Watcher, Dadseyes, Momseyes, Foureyes, and Groucho are clearly related in some way based on their nearly identical appearance, shared location, and very similar Japanese names. However, this relation is never explicitly revealed. The existence of a seemingly disembodied pair eyes acting on its own is never revealed either. All of these enemies are only seen in the bizarre land of Magicant.
"This enemy's face is the easiest to draw."