Squash

The Squash is a single-use plant that attacks zombies in a tile directly to the left or right of it by squashing them.

The Squash appears to be loosely based on the Butternut Squash [1], one of several species of Cucurbita maxima.

Usage
When planted, the Squash waits until it sees a zombie in an adjacent square (to the left or right), and then pounces, destroying itself and dealing huge damage to all zombies on that square. It may not work on the left side, but always the right.

Suburban Almanac Entry
Squash

Squashes will smash the first zombie that gets close to it.

Damage: massive

Range: short range, hits all zombies that it lands on

Usage: single use

"I'm ready!" yells Squash. "Let's do it! Put me in! There's nobody better! I'm your guy! C'mon! Whaddya waiting for? I need this!"

Cost: 50

Recharge: slow

Standard Levels
The Squash is an excellent plant to use in early setup against that one zombie or tight group of zombies which are too strong for the current defense or that managed to sneak through. However, plant slots are generally too valuable for this plant to be of frequent use in earlier levels, though they are good against Gargantuars and Zombonis, and are excellent for Survival: Endless after you finish your setup. The Bobsled Bonanza Mini-game is one level that the Squash really shines on (although some setups need no Instant Kills at all), because of its relatively cheap cost and ability to destroy a Zomboni, but it only squashes one or two of the Zombie Bobsled Team in one hit, so use a Wall-nut or Tall-nut to make the zombies stack up. It is also helpful in the Column Like You See 'Em and Pogo Party Mini-games. One thing to remember is not to stack Squashes in one lane. For example, in the Roof levels, if a Bungee Zombie drops a zombie in the middle of the Squashes, two or three Squashes will squash only one zombie.

Vasebreaker: Another Chain Reaction, Ace of Vase & Endless
These levels absolutely require that you use the Squash, due to the presence of Gargantuars. Whenever you see a Gargantuar, hit it with two Squashes as quick as you can. Don't forget you can even plant the Squashes directly under the Gargantuar, and it will hit it before it has a chance to react.

I, Zombie Puzzle levels
There are several I, Zombie levels with Squash. Make sure you use cheap zombies whenever you can, and remember that the Gargantuar can be easily taken down by two of them in the same lane.

Trivia

 * The Squash can take unlimited chewing, and can withstand the smash of a Gargantuar.
 * The Squash can be destroyed by Peashooter Zombies, Gatling Pea Zombies, Jalapeno Zombies, basketballs, and Jack-in-the-Box Zombie explosions.
 * If a Squash squashes a Peashooter Zombie or a Gatling Pea Zombie, they will shoot into the air triing hit the Squash
 * In the online version of the game, you get the Squash instead of the Potato Mine after Level 1-5.
 * For some reason, the Squash never squashes Bungee Zombies to the left. This may be because, like when a Bungee Zombie targets a Chomper, it drops slightly behind the plant.
 * Squashes deal almost full damage to Tall-nut Zombies, leaving them about with about a third of their health left, approximately 48 attacks.
 * Squashes are only available on the full version of Plants vs Zombies.
 * Only an Imitater Squash that is transforming can be eaten, run over or smashed.
 * If a Squash is squashing a zombie in the water, it will create a splash.
 * If you quickly plant a Lily Pad on the same square of a zombie, and then plant a Squash on the Lily Pad, the Squash will create a splash on the Lily Pad.
 * If you plant a squash on a Lily Pad on the first/last column of the pool to target a zombie outside the pool, the Squash will kill the zombie but it will still create a splash even if that zombie is already walking and not swimming.
 * The Squash is the only plant that doesn't mirror its image when facing the left.
 * The Squash, the Chomper,the Tangle Kelp and the Potato Mine are the only Instant Kills that are activated on contact with the enemy.