Pastis is an anise-flavored liqueur from France, typically containing 40-45% alcohol by volume. When absinthe was banned there in 1915, the major absinthe producers (then Pernod and Ricard, who have since merged) reformulated their drink without the banned wormwood component, creating pastis, which remains popular in France today.
In France, pastis is diluted with water before drinking. The resulting decrease in alcohol percentage causes some of the constituents to become insoluble, which changes the liqueur's appearance from dark transparent yellow to milky soft yellow.