switcheroo (noun)

1. During their candlelit dinner, he made a sudden switcheroo and presented her with an engagement ring instead of a dessert.

2. The interior designer suggested a switcheroo in the layout of the living room to create a more open and inviting space.

3. In the middle of the story, the plot took a switcheroo when the hero's sidekick turned out to be the main villain all along.

4. The film's climax featured a dramatic switcheroo where the protagonist's long-lost twin was revealed as the mastermind behind the crime spree.