Overwatch's Reinhardt has one of the most powerful ultimates that allow for team fights (or team kills) to initiate: Earthshatter. This ability, along with the durability of his shield, has given him a spot in the professional scene (and a casual one.)
One Reinhardt player in particular has found a new way to use this ability. Now, the ability does have a casting time and can either blocked by a barrier (such as Orisa's, Winston's bubble, Symmetra's ultimate and Brigitte's shield), or enemy players can move aside when they hear the audio cue of "Hammer down!"
One player has found a trick around the casting time, and that is to cast the ultimate against certain structures and wait (as shown in this clip.) Twitch streamer Mcmagicmarv casted it against a pillar in the second point of Temple of Anubis, waited a few seconds, and then move in order for the hammer animation to complete and stun the enemy team who was unprepared.
Temple of Anubis is not the only map where he can use this Reinhardt trick: in Ilios, the streamer managed to pull this off by using the same principle as before: ulting, letting the "Hammer Down" audio trick his opponents, and then waiting until he can move to cast it.