Alfamannen is Norwegian for "Alpha male". The event wants to be associated with: the man, boys childhood play, test of manhood, a very demanding challenge and test of strength, hard trail run, mud, travel, movement, persistence/endurance, play, energy, joy, hunting, the Viking Age, Norway, the military.
Alpha male is the boss, the leader of the group. The term was first used about wolfs.
The race will include a mud track at a military camp, and an old silver mine (tunnels).
Look at
http://www.toughguy.co.uk/ for inspiration.
The letters must be very easy to read, very visible.
The mascot should be a man, full body or face only. He could look like a viking (but with no helmet), or a special force military soldier (with no cap), or a worker in the silver mine (but with no tools). He must be the powerfull rather aggressive boss. Any alpha male (and participant at this event) should say that "this mascot IS me" and use it as a tatoo...
The mascot should symbolize the leader you want to protect you during time of war. It could be inspired by Clint Eastwood, Indiana Jones or Maximus in The Gladiator. But not Tarzan, Spiderman, Superman or Batman.