Because then it ' s saying stuff like Shazam can ' t kill him . Like if he tried to punch him , his fist would just reverse on itself and smash himself in the face . Or that he ' d beat Saitama because his sword would be struck by lightning and he ' d electrocute Saitama with the power of Grayskull or something . Remember , the prophecy is none woman born shall harm Macbeth . So they can ' t even hurt him supposedly . <| sep |> Flashbang grenade could have caused that damage , the only difference between a FB and HE is fragmentation , the explosion of a FB is just directed out ports in the grenade instead of building the pressure inside until structural failure . If you hold a FB when it goes off you could easily lose your hand .