Spell: Arcane fog

[ollie444]

Magician casts the spell on an area of terrain. At the next turn, a 3x3 square of white fog appears over the area. One turn later, this increases to 5x5. Two turns after that, the fog disappears
All units concealed in fog (inc. enemy) have vision and movement reduced to 1 (movement because they could look to where they can't move, knowing that is where the enemy could be) and are unobservable from all units except units directly adjacent. Archers/catapults etc. can shoot anywhere in the fog, but will not know which has a unit underneath...

Moreover, you could have a way to fight this: eg. fireballs destroy fog, or an anti-fog spell.

[patroid]

Sounds cool.

[ejm29]

I like it!

[ollie444]

I'm not entirely sure the engine can handle it though...