Little (3.5e Trait)
From D&D Wiki
Unlike most members of your race, you are exceptionally small: A dwarf among your kind. The character is one size smaller than normal, and takes on all benefits and detriments of this size.
Prerequisite: Must be of a completely organic race
Benefit: The character takes on all of the benefits of being one size smaller.
Drawback: The character takes on all of the detriments of being one size smaller.
Normal: A Character normally is restricted to the size of its race.
Roleplaying Ideas: Silhouette, a Catfolk, is a rather small individual, given his race's normal stature. Due to his small size, he's rather easily captured or pinned, but is exceptionally capable at sneaking about and slipping through the cracks of most structures.