Fog/mist spell!

So basically this is the de version of the freeze spell it slows down defense and cc troops similar to poison except it also targets defences. It also stacks up. It has 4 levels, and 3 stats attack speed increase(100% = double), speed reduction and cost at level 1 the stats are 60%, 5, 350 in the order above, level 2: 80%, 6, 395, level 3: 90%, 8, 430, level 4: 100%, 9, 500. If you think this is too op or weak just tell me.

It would be a good spell if on offense it covers a area for 20 seconds and made the defenses in that area miss 50% of the shots