In Magic the Gathering: Puzzle Quest, what does the Objective "Defenseless: Summon no creatures with 0 during a single fight" mean? I've apparently achieved it on at least one battle, but I have no idea how. The grammar doesn't really make sense.
Looks like this is a bug. The '0' should be the symbol for 'Defender' which are creatures that your opponents creatures must attack instead of you. This makes the description of the Objective "Defenseless" make much more sense.
It means that you did not "hold" a creature to summon and instead summoned it immediately when you could so if you had a creature that needed 3 mana and you matched 4 and you had either "grayed out" the summon or there were already 3 creatures on your side you decided not to summon the creature that turn.
That creature when summoned will be considered "summoned for zero"