Excursion Funnel

The Excursion Funnel is a game mechanic introduced in Portal 2. The mechanism creates a wide beam of blue light that the player may enter or exit at any time. It seems to defy the laws of gravity, allowing any who enter to become weightless and travel along the path of the Funnel. Anyone or anything caught inside the Funnel travels in the direction that the Funnel is flowing, unless the Funnel is made to reverse, which is usually accomplished through the activation of a button.

An Excursion Funnel

Excursion Funnels can pass through portals and can cross vast distances, and can therefore can be used to solve puzzles in which Funnels may not initially appear to be useful.

Excursion Funnels can also act as a mode of transportation for the player or objects across large gaps, as well as Gels. Gels caught in the Excursion Funnel will slowly follow the direction of the Funnel until the substance collides with a wall or until the Funnel suddenly disappears, making funnels useful for coating large areas in a short amount of time.

Trivia

When inside an Excursion Funnel in the single player campaign, soothing music plays, possibly to relate the tactile sensation of being weightless in a funnel. All other sound is blocked out or significantly dampened.

Because of the fine print in the early Portal 2 trailers, many people have come to believe that the funnel is made of liquid asbestos. This theory is supported by the liquid ambiance one hears while traversing a funnel, but is refuted by the fact that the funnel does not exhibit any other liquid qualities and does not refract light in the way clear gel or water does.