Maguey worm

From Distillers Wiki

A butterfly which can live in the agave plant during it's pupal stage. Maguey worms have been enjoyed as a tasty and nutritious fried or roasted snack for centuries. There is a salt called "worm salt" which is mixed with pulverized maguey worm and is enjoyed by mescal drinkers who like to add it to their drinks. In the United States, store-bought salt is used on the rim of most margerita glasses.

At some point the worm was introduced into mescal bottles in order to devour any evil spirits which might be hidden inside the spirits, so to speak. Aside from this, it turned out to be a unique identifier and thus a great marketing idea.

The mescal-soaked worm has been given a reputation as an aphrodesiac and as being hallucinogenic or psychoactive, but these are simply rumors. The ritual of eating the worm after finishing a bottle of mescal is more popular outside Mexico where it is often considered unusual.

Tequila is a type of mescal produced exclusively from the blue agave cactus in the state of Jalisco in Mexico, but since it lacks the familiar worm is not commonly thought of as such.