MArcomage

Interesting. If one of the opponent's facilities is already at 1, will it only target one of the other two, or would there be a chance of it trying to reduce the one that's already at it's minimum? (In other words, if facilities are 1,1,2, would it be a 100% chance of reducing the dungeon, or is there a 67% chance that it has no effect?)

I've never had a game in that situation, but either works for me. Alternatively, it could reduce the highest facility by 1, removing that problem. Any would work for me.

I had to think of Locust Swarm when reading this card. What would you think of swapping the lines (and maybe boosting the attack, since the condition is harder).

Attack: 10.
If enemy wall = 0, random enemy facility -1.

Would become
If enemy wall = 0, random enemy facility -1.
Attack: 10(+?).

If enemy wall = 0, attack: 15, random enemy facility -1
Else
Attack: 10

Or like that. ;-)
The idea is about the same.