Teaser

Noun

1. One who teases or pokes fun.
2. A person or thing that teases.
3. A preview or part of a product released in preparation of its main advertising, typically a short film, song, or quote.
4. A brief portion of a television episode or video that is shown at the beginning, often before the main title sequence, meant to introduce the story and entice viewers to watch the rest of the episode.
5. A kind of gull, the jaeger