A sentence in which the ideas fall, or become less important and striking, at the close; -- the opposite of climax. It produces a ridiculous effect.

Like a climax, an anticlimax is the turning point in a story. However, an anticlimax is always a letdown. It's the point at which you learn the story will not turn out as you expected.

a change from a serious subject to a disappointing one

a disappointing decline after ad previous rise; "the anticlimax of a brilliant career"

When the audience is led to story crescendo that fails to deliver and leaves them feeling disappointed.

Anything that happens in the final few moments of a film that dulls down the story crescendo and leaves the audience feeling let down and unsatisfied.

producing a big anything in hopes of instantly intensifying the climax of a magic trick (See Flop Sweat.).