It is hard to say exactly why this drink is called El Diablo (Devil in Spanish), perhaps it is its red color, or perhaps it's due to the little bit of spice brought in from the ginger ale. Either way, this is a wonderfully refreshing drink, and a good way to introduce somebody to tequila.
1 1/2 oz Tequila
3/4 oz creme de cassis
1/2 oz lime juice
Shake first three ingredients with ice.
Strain into a collins glass filled with ice.
Garnish with a lime wheel.
Top with ginger beer.