Ariel, the spirit, sings before Ferdinand who is mourning the supposed death of his father by drowning. The visual imagery employed to describe the metamorphosis of the dead person into an exquisite object of beauty is important. We know Ariel is just playing a prank on the Prince telling him that his father is dead but Ariel looks at the death of this mortal as a transformation into something rich and strange. His bones are corals and his eyes are pearls and nothing of him changes except into something rich and strange. The unreality of the supposed death is part of Ariel’s world, which is of the spirits, being the stuff dreams are made of.

‘Full fathom five thy father lies
Of his bones are coral made
Those are pearls that were his eyes
Nothing of him that doth fade
But doth suffer a sea-change
Into something rich and strange’

William Shakespeare ~ The Tempest