Ah! Lord Beerus! is a feint that appears in Dragon Ball Fusions.
The user performs a feint where they pretend the God of Destruction Beerus is behind or nearby their opponents, taking advantage of peoples' fear of Universe 7's God of Destruction to catch them off guard.
In the second chapter of Dragon Ball Side Story: The Case of Being Reincarnated as Yamcha, Yamcha (Reincarnated) utilizes this technique in order to gain an advantage over Vegeta.
Video Game Appearances
Ah, Lord Beerus! was named and first appeared in Dragon Ball Fusions as a Special Move and stronger variation of Ah, Lord Frieza! (which omits the Energy Barrage as it is depicted as a simple feint in Dragon Ball Fusions) capable of cancelling action of all enemies around the user. Due to gameplay mechanics, this technique can ironically be used against Beerus himself.