2920. The 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 Squash.
When planted, the Squash waits until it sees a zombie in an adjacent square (to the left or right), which will be known, as the Squash's eyes will turn around to the zombie and make a "hmm?" noise as if disapproving, and then it will pounce, crushing the zombies in that square.
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.
You got a Squash!
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.