From Distillers Wiki
The snakebite is a cocktail made from lager and cider (what is known as hard cider in the US).
The basic snakebite is a mixture of equal parts of lager and cider (or alternatively a one third-two third mix), typically served in pint or half-pint servings. It has a reputation of being a "hard" drink, but the appeal of the drink seldom lasts into maturity and it is predominantly drunk by late adolescents.
In the snakebite and black (also known as snakebite, black) variation, a shot of blackcurrant cordial (or Creme de Cassis (Crème de Cassis) is added before mixing in the beer and cider. Alternative variations can be made by using Benedictine or green Chartreuse liqueurs instead of the Crème de Cassis.
There is a far more potent version of snakebite known by many names (such as deadly snakebite, hard snakebite, or super snakebite). This is made by combining a super lager with an ABV of at least 8% (usually Special Brew or Tennent's Super) with a cheap cider such as White Lightning. The resulting concoction will get the drinker very drunk very quickly, but also has a very strong taste and if drunk with any regularity, will combine the powers of super lager with those of cheap cider: at the very least, the hangover the following morning will be extremely unpleasant.
See also: list of cocktails