In a dungeon or tower, a spinner is a type of obstacle designed to hinder the party's movement.
Spinners rotate a party's facing in a random direction, briefly confusing the Kiel's Magic Compass spell if one is going. When encountered within darkness zones, they can be particularly disorienting.
Spinners can be defeated if a member of the party has a Nospen Ring (Nospin Ring) equipped.
In Tales of the Unknown, the Second Sight spell doesn't specifically identify spinners as such; it only reports them as "Something special is near...".