I want to add in my game the toxic gas… ( i want to make a battle royale and in battle royale the gas is essetial )
Example1 : https://www.youtube.com/watch?v=COVDDdmgevY - 2:25
Example2 : https://www.youtube.com/watch?v=ssEK7u6iX9c
Some tips guys?
You didnt look into a single free content project did you?
Besides various kinds of fogs which the engine can do out-of-the-box, hundreds of similar particle effects are provided in free assets in Infinity Blade Effects/Fire/Ice/Grass lands etc.
maybe i have the design gass but im not sure… Animated Materials in Materials - UE Marketplace (Lava Shader is yellow but maybe is easy to change in green collor)
“You didnt look into a single free content project did you?” ?? i dont understand you mean, i can find ? is exist? is free? if someone can make this for me… sure i pay 
You can pay if you wish, but the assets are free and available right in your Launcher. Just look for the Infinity Blade stuff.
you mean this? Content Search - UE Marketplace
And you are say is free but what? the effect or the system?
i
The entire thing.