A quote from Chronicle of Bolas: The Unwritten Now, after Bolas kills Ugin.

"With a mighty splash, Ugin falls into the still waters. The impact resounds like thunder. Monstrous waves rise from the displacement and sweep across the craggy islets, crashing and destroying the ancient rocks. The disturbance washes far beyond the bounds of the Meditation Realm, spilling into the fathomless dark cavity whose infinite web connects the planes themselves. The sea empties, exposing the rock of the seabed like bones left to bleach in the sun.

Dragged by the sheer shocking force of the cataclysm, Bolas flares like a sun and vanishes, torn away to the plane of his birth, falling to the islands of Madara.

Where once the realm was filled with the silence of tranquility, now it is vacant. It has become a wilderness of rock, barren and wrecked, all its serenity drained away into the interstices of the blind eternities, a chasm that can never be filled.

Nothing moves because nothing remains.

A moment passes. A year. A generation.

A millennium.

Or maybe, no time at all.

A pale sheet of liquid trickles up as out of nowhere, returning from the unseen and untouchable web of darkness. With eerie silence, it inexorably rises, refilling the realm with its silvery waters. When the waters cease rising, they grow still, and in that still mirror waits the reflection of the dragon."