This small shot mug is shaped like an oyster and marked for "Inside Passage" on bottom. Made by Trevor Foster Studio.

From Inside Passage:

"The Oyster Shooter Shot features spirits for two of our favorite briny friends: Trois Rivières Cuvée de L’Océan rhum Agricole and Astraea Ocean Gin.

Salty, and fresh from our house lemongrass syrup, with a little hint umami from the manzanilla sherry and kelp, it’s the best tasting Oyster Shooter you’ll ever have!

Shot glasses, made by the mug virtuoso Trevor Foster Studio, also available for purchase. Two color ways (blue wipe and gray wipe), $35 each."

Later advertised on their website for $30 if $10 shot is purchased along with it ($40 total).