Cattails can attack any lane of zombies, not just that which they're planted in. So how do they choose which zombie to attack?
I'm not 100% sure, but whenever I used them they seem to attack zombies in this order:
- Whatever is attacking it (self-preservation, although this could just be point 3 below as well)
- Balloon zombies if any appear
- Zombies that are the furthest down a particular lane
- Pick a target at random (if they're all nomming on Wall-nuts)