He seems to be based on the unused Dog Walker Zombie found in the data of the first game.
His description could possibly be a reference to Garth Nix's quote "Does the walker choose the path or the path choose the walker?" in the fantasy novel Sabriel.
Statistics
Class: Beastly
Tribe: Pet Zombie
Trait: Hunt
Abilities: None
Set - Rarity: Premium - Uncommon
Card description
Is the Zombie walking the dog, or is the dog walking the Zombie? Hard to say.
Update history
Update 1.14.13
Set - Rarity change: Basic - Common → Premium - Uncommon
Update 1.16.10
Ability removed.
Trait added: Hunt (Same effect as previous ability)
Strategies
With
Dog Walker is a good starting zombie, but not for attacking your opponent. Instead, Dog Walker shines at preventing your opponent from playing cheap setup plants like Template:PvZHLink, Poison Mushroom, Template:PvZHLink, or even Haunted Pumpking, as Dog Walker goes to that plant's lane and disposes of it. Giving him stat boosts or the Deadly trait helps him destroy tougher plants, while giving him the Frenzy trait lets him hurt your opponent if he can destroy the plant fronting him. However, you will have to beware of instant-kills and Bouncing in this case.
However, Dog Walker's Hunt trait can be easily exploited once your opponent generates enough sun to play multiple plants, especially if they have good, or reliable card draw. Dog Walker cannot be expected to survive long either, since he will always be fronted by a plant unless none are played that turn.
Being a pet zombie, Dog Walker can also be used as a cheap way to activate Zookeeper and Cat Lady's abilities.
Against
Dog Walker can be hard to counter due to his Hunt trait, especially if you have plants that either need to survive like Party Thyme, or those with Anti-Hero (especially Poison Mushroom and Poison Ivy). However, he is also very easy to destroy thanks to that; any plant that does 2 damage like Template:PvZHLink is enough, as Dog Walker will move there and be destroyed.
Later on, be careful of the order you play cards in when Dog Walker is on the field, as you may want certain plants to survive or attack your opponent directly, and others to combat Dog Walker.