by Janie — Norse mythol­ogy, the god­dess Freyja has a cloak of feath­ers that can ferry her be­tween hu­man and fal­con forms. The Aztec de­ity Tez­catlipoca some­times wore a jaguar skin to dis­guise him­self. Sneak­ing into the ranks of such mytho­log­i­cal fig­ures is the more tan­gi­ble and much smaller Group A Strep­to­coc­cus...