Wall-Nut

Wall-Nut (or sometimes Wall Nut, Wallnut, and Walnut) is the fourth plant the player obtains/ receives in Plants Vs Zombies. It is the plant found after the Sunflower and Peashooter in Plants Vs. Zombies and its sequel. Later in the game, Wall-Nut has another plant that is more defensive, taller,and can't be vaulted over by (Pole-Vaulting Zombie, and Dolphin Rider Zombie, etc.)

Wall-Nut is also the first defensive plant to obtained next to Tall-Nut and Pumpkin. It takes about 20 seconds for a Wall-Nut to be eaten by a Zombie.

Appearance
Wall-Nut appears to be a yellow-brown-ish color. He is a little oval-ish in shapes. And he has a smile and white irises with black pupils for eyes. It is obviously based off real life Walnuts and their defensive hard shells.

Plants Vs. Zombies
In Plants Vs. Zombies 1, Wall-nut is obtained at the end of 1-3 and begins to be avalible for the player to use at the next level, 1-4. It is commonly used with the strategy a offensive plant attacking the zombies while their chewing on the Wall-Nut. It is also placed behind Spikeweed. When zombies are eating Wall-Nut, they are taking damage by stepping over the Spikeweed.

Plants Vs. Zombies 2: It's About Time
In Plants Vs. Zombies 2, Wall-Nut has the same role with a new design and a minor effect in the game which is why people like Wall-Nut. Now he stares all around the screen while he is eaten, or being eaten. Wall-Nut has brighter colors, more rocky-like shell and a smile with visible eyebrows.