From the Wikipedia article 
Jagertee (also Jägertee) - or hunters' tea - is an alcoholic beverage made by mixing overproof rum with black tea. It is served warm and is typically consumed during winter in the cold parts of Central Europe.
Although Jagertee is easily made at home, ready-made mixtures which also contain sugar and spices are sold in shops. The Austrian Stroh rum is often used for making it; this brand also produces its own ready-made variety.
Jagertee has become a popular après-ski drink, especially among tourists in the Alps, where it has caused some serious skiing accidents when taken avant-ski.
Some rural establishments also serve Wilderertee ("poacher's tea"), which is even stronger.