Winter's Sting Pistol Skin
From Guild Wars 2 Wiki
“Double-click to consume.
Seasonal. For sale only during the Wintersday season. Use anytime to upgrade the appearance of a pistol. Usable only by pistol wielders.
— In-game description
All Wintersday wooden weapons have a wintery snowflake glow as well as a pulsing white branch design. The pistol's branch design flows around the pistol's barrel. A picture of the pistol's glow can be seen here.