Bathos (noun)

1. A sudden and unexpected drop from a lofty or elevated style or tone to a commonplace or trivial one; a descent from the sublime to the ridiculous.
2. A silly, banal or ridiculous effect produced by a failure to maintain a consistent level of gravity, dignity, or tone.

Origin:

Derived from the greek word 'bathos' meaning 'depth'.

Examples:

1. The novel was filled with moments of bathos, where the serious mood was broken by a silly turn of events.
2. The play was going well until the final scene, which was filled with bathos and ruined the performance.
3. The politician's speech was well received, until the end when a moment of bathos made everyone in the room laugh.
4. The singer's performance was filled with bathos, alternating between high-pitched opera-style singing and silly pop songs.
5. The movie started as a serious drama, but descended into bathos in the final act.