Lingering potion effect for gasses?

[JoeyDP]

The visualization of lingering potions could also be used for gasses. However, gasses will likely also need to move and interact with the world. Is it possible to create a gas that disperses and goes down when possible using the lingering potion effect?

Look into whether this is a feasible option for implementing gasses. Additionally report on whether this solution can scale (many entities required? update lag?) and is flexible to extend with new features and interactions in your opinion.

As an example you can implement mustard gas that disperses and damages entities it comes into contact with.