The Wedding-Guest fears the Ancient Mariner in Samuel Coleridges poem Rime of the Ancient Mariner for three reasons. The first is that (1) the Mariner grabbs the Wedding-Guest--a perfect strange--with his skinny hand and starts talking about "There was a ship." This is pretty spooky all by itself. The Wedding-Guest becomes really frightened when (2) the Mariner fixes him with a look from his "glittering eye."
The Mariner's "glittering eye" and correlated look are so awful that the Wedding-Guest stands stock still, unable to move. Finally, he is frightened because, even though he dearly wants to be at his relation's wedding and can plainly hear the bassoon begin to play the bridal march, (3) the Mariner "hath his will" and he is unable to move.