Sea Change

"Sea change" is a common phrase that usually implies a dramatic transformation, like a tidal shift. But its origin is poetic, from Ariel's song in The Tempest," and is a bit grim. Its basic meaning is that of a gradual, progressive change in substance while the form is preserved. But a great writer can make the worst "rich and strange."

Ariel tries to comfort Ferdinand after his father drowns:

"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,
Sea-nymphs hourly ring his knell,
Ding-dong.
Hark! now I hear them, ding-dong, bell."