Jetstream is a recreation of the Fuzion Frenzy minigame with the same name. Players have to dodge debris that falls from the "waterfall" and outlive their opponents against a backwards-flowing current.

The basic goal is to survive longer than your opponents while in a ghost. This could either be by just straight up dodging the falling debris, or by intentionally knocking a rival off the edge.

As there is no flowing water or gravity zones in Halo 3 forge, to make the players "flow" backwards I built the entire thing on an incline. If players are not boosting and try driving horizontally, they will slowly go down the ramp; gravity acts as the water in this case.

Looking at it now, the gamemode is honestly a combination of Monster Trucks/Lava Pit and Avalanche/Landslide.

Monster Trucks

Push players to their death ✔

Avalanche

Dodge debris that is falling down the ramp ✔

GAMEPLAY (starts at 06:29):

DOWNLOAD:
To get this map on console, follow the first instructions. If on PC, follow either the first or second instructions.

1. (Xbox/PC) In-game: When in a lobby, go to the roster, click on your name, and click on the "Find Player" option. Type "RushMyPancake" and view my File Share. The map and gametype will be in each respective section. Download them. Ignore the warning message that may pop up; that's because I made the maps on PC.
2. (PC ONLY) Download the files posted through the download button on this thread and drag them into their respective folders in your game files.

For me it is:

Map:
D:\Program Files (x86)\Steam\steamapps\common\Halo The Master Chief Collection\halo3\map_variants

Gametype:
D:\Program Files (x86)\Steam\steamapps\common\Halo The Master Chief Collection\halo3\game_variants

OR put them into %userprofile%\AppData\LocalLow\MCC\LocalFiles