poster child (noun)

1. The poster child for modern architecture, the Sydney Opera House is an iconic landmark.

2. In the magical realm of Eldoria, Aria the poster child of light magic battles against the forces of darkness.

3. The haunted house on Elm Street became the poster child of horror movies with its terrifying ghostly presence.

4. Superhero comics often feature a poster child, like Superman or Spiderman, as their main protagonist.