The singular attack of Breath of the Wild's 'Guardians' is the Light Beam. it is an extremely powerful attack that has the capacity to one hit kill you at a level.

Though yes it is terrifying to be chased down by one of these as it sets the grass aflame and mows down trees as it desprately charges after you with bloodlust, their immensly powerful beam can actually be parried.

By parrying with your shield at JUST the right time you can send their Light Beams of destruction right back at them causing it to deal a full third of their health. this trick is hard to perfect but for a parry master like myself, Guardians have become more of a fun activity than a threat (though when i have no shield i'm screaming in terror as they chase me down at speeds that i'd say are completely terrifying!)