Unassuming

You are small and unassuming, and often ignored or overlooked by the larger races.

When you are in combat with opponents that are size medium or larger, and fighting alongside two or more allies of size medium or larger, any opponent of size medium must succeed on a DC13 perception check ar the start of each of their turns. 

A failure means they have temporarily lost track of you, resulting in disadvantage on their attack roll.

This feat does not apply to opponents with blindsight or tremorsense.