v21.1 How do you program a location to give all Wild Pokemon and Battles a permanent "Tailwind" effect against the player?

[SuperSpyroDragon64]

I tried programming it myself, but that crashed the game.

How do I create a location where the wind is always blowing in the enemy's favor, doubling the speed of all foes?

And how can I make this also work in an area with a permanent terrain and weather effect no battler's moves can change?

 

[SuperSpyroDragon64]

Also how do I add Permanent Rain and Permanent Electric Terrain to the effect?

This area is supposed to be hard. If the player can change the rain/terrain/remove or outlast tailwind that's lame.