A device by which the audience or a major character (or both) gets a brief view of other major characters who have yet to appear in the story: an optical effect gives the sense of a moving tube or tunnel, down which translucent or opaque images of various characters swirl and recede. When not found as part of the opening credits, the Tunnel is usually the result of some mind-altering experience, such as the process of being Trapped in Another World.
- The opening credits of Prétear.
- Similarly, the opening credits of Dual! Parallel Trouble Adventure has a brief tunnel-like sequence.
- Makoto's transfer to El-Hazard in El-Hazard: The Magnificent World.
- The very first scene in the Read or Die TV series.
- A character who appears in a single episode of Neon Genesis Evangelion appears for a split second in the opening credits of the series.
- Rei's appearance early in the first episode of the series might count as well.
- S Cryed: Most versions of the opening sequence, but the opening changes both as the story progresses and acording to which character has the spotlight this episode.
- Little Witch Academia (2017): While traveling through Yggdrasil's roots, Akko experiences a vision of events that haven't happened yet, including a brief shot of the show's final villain in silhouette.
- The Flash: Professor Zoom's time-rips showed Bart Allen in the Kid Flash costume several months before he started wearing it.
- Fairy Tail Redux: Salamander's Time Traveling Escapades: Chapter 35 gives us Mavis.
- In Doctor Who episode "The Parting of the Ways", temporarily super-powered Rose gets a glimpse of the Tenth Doctor (David Tennant) in a similar optical effect, several minutes before Eccleston's Doctor actually regenerates into him.
- Lapfox Trax: Accidentally; in the album Rainbow Dash Likes Girls there is a song called TRUXXXXXXTON which later ended up being an alias.
- Should be noted that the name of the alias is just Truxton, not TRUXXXXXXTON.
- Literal example: If you stand in the three tunnels to each island in Crackdown, you can hear the bosses of those islands cursing you out.
- The openings for Fire Emblem: Path of Radiance and Fire Emblem: Radiant Dawn.
- The Legend of Zelda: Majora's Mask shows silhouettes of the game's various transformation masks flying past the screen after Link falls down a very, very long hole at the beginning of the game.
- In the opening sequence of Futurama, a brief moment when the camera reveals a long tube (used for transportation) features many recurring characters, including Amy, Hermes, Dr. Zoidberg, and Zapp Brannigan, all of whom didn't originally appear until after the pilot episode.
- The pilot for Tiny Toon Adventures, "The Looney Beginning", had Buster and Babs open a trunk full of villains, many of whom they would encounter in later episodes.