The Australian Football League grand final is tomorrow. All year, two teams of men have been training and lifting weights; growing strength to be harder and stronger at the contest. They needn’t have bothered. WADA, the world drug testing authority, currently don’t list berserker mushrooms on their list of banned substances. In ancient times, Norse vikings would eat a pile of these things before battle, causing a boost in head-lopping capability. Nick Riewoldt, a flaxen haired warrior who looks like …