It is (apparently) illegal
for a bar or pub
in the UK
to serve you a snakebite, such is its potent power. It doesn't taste that bad (the badness of lager
and foulness of cider
cancelling each other out) leaving you with a big fat pint of pretty strong mixed drink.
Of course, you can just make your own by ordering a pint of each and then mixing them into a conveniently previously-downed glass, or heck, just drink half of each 'properly'. They can't stop you doing this (in the same way they can't add spirits to a pint but you can dump a nice double vodka into your Boddingtons if you want).
For the ultimate headfuck, a snakebite made with a can of Special Brew (9% ABV) and a can of White Lightning (7.2% ABV IIRC) tastes surprisingly harmless but will happily screw you up in no time.
So, a good drink if you are going to a crappy club with people you hate and have five minutes to get loaded before heading out.