Smoke reduces the visibility and therefore the effective range of an enemies defenses.
Smoke would be available to be bought first at th10 as the next available Dark Elixir spell.
It will be available at 3 levels which each reduce the effective range of those it targets by greater amounts.
The first two levels of the spell are available at TH10 and the third is available at TH11.
The first level of Smoke reduces range of defenses by 1/4.
The second level of Smoke reduces the range of defenses by 1/3.
the third level of Smoke reduces the range of defenses by 1/2.
This range reduction would last for 20 seconds.

