Ringing of the Bell

As part of a ritual or seance or something a cleric rings a handbell. Chant chant, ring, chant chant, ring, chant chant, ring.

At first this seems normal.

But then shadows start to deepen, and visions blur. The voice becomes modulated and difficult to parse. Then the bell rings out before the clapper meets the bell. Speech runs backward. Magic, blah blah, very atmosphere.

When the bell has rung X times, event.