Hi All,
The Force Bash pushes and slams one creature into another.
The first part of the spell Pushes a target creature. Handle it just like a Force Push:
If a non-flying creature is Force Pushed it will stop when it hits a wall, if that wall has has the Passage Blocked trait (such as a Wall of Stone, or the outside walls of the arena). In this case it does get Bashed (3 dice unavoidable attack).
If the same creature is Pushed into a wall with the Passage Attacks trait, it also stops, unless you paid 3 extra mana when you cast the spell. (This represents the spell requiring additional power to Push it through an attacking wall.) If you pay the extra mana, the creature pushed through the wall. It receives the attack, and then is moved into the new zone. If the extra mana was not paid, the creature is not pushed through the wall, and remains in place. (Yes, this may seem a little weird. This rule is there for game balance - wall attacks were too powerful in playtesting without the extra mana requirement.)
Force Push on a flying creature will Push them one zone, and they ignore all walls, except the outside arena walls. They are not bashed or attacked by walls, unless Pushed into the outside arena walls.
So, first handle the Force Push part of the spell, exactly as a Force Push is handled. Once that it done, then the second part takes place - the Slamming!
The target creature receives the Slam condition. And, any other other target creature in the new zone it enters may also receive the Slam condition. This occurs after the Force push part, and after the creature is moved into the new zone.
Visualizing this, they are both slammed together and would actually receive the Slam condition at the same time. That is the spells intent, although mechanically you first place a Slam on the original target creature, then on the second target creature.
If there are no enemy creatures in the new zone, then the spell is effectively slamming them into the floor, and this occurs after they have moved into the new zone.
Yes, it can target a flying creature and Slam him into a non-flying creature, or visa-versa. Again, this occurs after the first creature is Force pushed. For example, a non-flying creature is first Pushed one zone, then is "raised" and slammed into a flying creature (or visa-versa).
Hope that helps! Please let us know if you have any further questions.