Carrculator

Carrculators can show a zombie's health by planting one on a specifc zombie.

Strategy
This is REALLY helpful if you don't know how much damage you need to kill a zombie. Say, you didn't know the Mecha-Football Zombie's health, plant one of them on that and you'll surely know how to deal with it!

Trivia

 * The leaf part of Carrculator resembles a plus sign (+).
 * Carrculator is a portmanteau of carrot and calculator.
 * When this plant is selected, all the zombies currently on the lawn turn gray-ish, and when you plant it on a gray-ish zombie, the Carrculator plants on that zombie.
 * ​If a zombie is just about to go to the lawn, it will turn gray-ish as well when it steps on the tiles.
 * ​The zombie will also stop moving and attacking plants will ignore it.