Thieves

From Zelda Wiki.org

Not to be confused with the term "Thief" used in Link's Awakening.

In A Link to the Past, there are thieves in the game that can steal rupees, bombs and arrows from Link whenever they touch him. In addition, they do not cause harm. When they glance at you they will chase you until you are a considerable distance distance away. They can be found in a human-imp shape in the Lost Woods and in the Village of Outcasts with a fox-like form. You can stun them with your sword or a long range item (such the boomerang) for a short time, but unfortunately they are virtually invincible.

Thieves found inside caves or underground stumps typically offer rupees. A former thief assists Link by opening a locked chest containg an Empty Bottle.