The fen is an intelligent, man-sized fish, which walks about on 2 stubby fins when on land. It has both lungs and gills and may remain out of water for up to 24 hours. Its translucent skin makes the fen invisible when under water. Fens collect and use all manner of weapons and may also use their tail as a club which does 6 dice (d6) of damage if it hits. They are completely resistant to radiation, have a poison resistance of 18, reflect heat and light (laser) attacks for 5 melee rounds before taking damage, and can shapechange into a large bird and fly away if the going gets rough.