Chomper

The Chomper is a multi-use instant kill plant. It appears to be loosely based on Audrey II, the carnivorous, man-eating plant from Little Shop of Horrors, the Venus Flytrap, and the Piranha Plant from Super Mario Bros.

Suburban Almanac Entry
Chomper

Chompers can devour a zombie whole, but they are vulnerable while chewing.

Damage: massive

Range: very short

Special: long delay between chomps

Chomper almost got a gig doing stunts for The Little Shop of Horrors but it fell through when his agent demanded too much on the front end. Chomper's not resentful, though. He says it's just part of the business.

Cost: 150

Recharge: fast

Usage
The Chomper can eat any zombie other than a Gargantuar, Giga-Gargantuar or Dr. Zomboss in one bite - even Zombonis and the Zombie Bobsled Team. It will spend about 40 seconds chewing its meal, during which time it is vulnerable and cannot eat another zombie. However, if a Pole Vaulting Zombie (and another Vaulting Zombie) jumps over a Chomper, it will not be able to eat it unless it is frozen.

If a Gargantuar is in front of it, and there are no other zombies that the Chomper can possibly eat (apart from the Gargantuar), and it is not currently chewing, it will bite away at the Gargantuar and do small amounts of damage until it gets squished.

Standard Levels
The Chomper has a range of two squares in front of it, so it can eat a zombie on the other side of a Wall-nut, Tall-nut, or Pumpkin. Like all massive-damage plants, it's best against tough zombies, or for when a zombie manages to get past your defenses. The Tree of Wisdom mentions that the Chomper and Wall-Nut were roommates in college owing to the way that if a Wall-nut is placed directly in front of a Chomper, the Chomper could reach and swallow zombies just as they reach the Wall-nut. If you are trying to save space, plant a Pumpkin over the Chomper so that you do not need the extra space in front for a Wall-nut.

ZomBoogie (I, Zombie level)
Dancing Zombies are the most effective against the Chomper because they can continue to summon Backup Dancers. Just be sure to place the Dancing Zombie on the far right so that he will start summoning his Backup Dancers before he gets to the first row of plants, and to use a regular zombie first if there is a Chomper in the first column. When all else fails, use the regular Zombie to feed the Chomper, then eat it with another zombie.

All your brainz r belong to us (I, Zombie level)
There's no time limit on these puzzles, so plan your first moves carefully. There's usually only one lane with Chompers, so that's generally a good candidate for a Digger Zombie (remember - Chompers can't chomp behind themselves), but remember that there is almost always a Magnet-shroom close enough to steal the Digger Zombie's pick, so you may have to wait until you've earned enough Sun to afford a Bungee Zombie to get rid of the Magnet-shroom before you can send a Digger after the Chompers. Also, be warned: if a Chomper is in the leftmost column, it can eat any Digger Zombies that try to eat it.

Level 5-5 (Roof)
On Level 5-5 on the Roof, the Chomper is your only offensive plant here, but you also get Pumpkins, Cherry Bombs, and Flower Pots. It is best to put all of your frontwards Chompers in Pumpkins.

Trivia

 * No matter what type of zombie a Chomper eats, the arm hanging out of its mouth is that of a regular Zombie.
 * If a Gargantuar smashes a Chomper, no matter whether it is eating a zombie or not, its flattened version will always have no zombies or arms, and will have an open mouth.
 * According to the Tree of Wisdom, the Chomper and the Wall-nut were roommates in college, which is supposedly why they work well together.
 * On the loading screen, you can see saliva dripping from the Chomper's teeth.
 * The Chomper resembles a Venus Flytrap, which secretes enzymes into its trap to digest insects, so this can just as easily be digestive fluid, which may explain why the Chomper takes time to chew its prey.
 * Chomper is a male plant.
 * Chompers can't eat Gargantuars whole, but bite them instead and deal little damage. However, if a Chomper kills a Gargantuar, the Gargantuar will fall down as normal but the Chomper starts chewing with an arm hanging out of its mouth.
 * It might be the Imp.
 * The Chomper will do at least 3 normal damage to a Gargantuar.
 * It is unknown how a Chomper can tell if a zombie is in front of it due to the fact that they don't have eyes.
 * Although they could have heightened auditory or olfactory senses, or they could sense vibrations.
 * When an Imitater Chomper is eating a zombie, no matter what type of zombie an Imitater Chomper eats, the arm hanging out of its mouth is that of a regular Zombie, but it's black and white.
 * If a Chomper is planted directly in front of a bobsled, it will eat the sled, and all four zombies in it, which can be extremely helpful in Bobsled Bonanza.
 * According to the Plants vs. Zombies website, the Chomper costs 175 sun, while it really only costs 150.
 * The Chomper is the only plant that can kill a vehicle zombie without making them explode.
 * The Chomper is the plant with most teeth seen.
 * It is the only plant with pointed teeth. It is also the only plant that doesn't have eyes at all, and the only plant with a visible tongue.
 * The Chomper and the Cob Cannon are the only instant kills that are reusable.
 * They are the only multi-use instant kills.
 * Of the two, however, Chomper is the only instant kill with a fast recharge.
 * The Chomper, the Tangle Kelp, Potato Mine, the Squash and the Hypno-shroom are the only Instant Kills that can be used on contact to the enemy.
 * The Chomper is the only instant kill plant that is rooted to the ground.
 * The Chomper is the only instant kill that is unable to take away half the Gargantuar's health.
 * The Chomper is one of only four plants that have a name which doesn't involve plants or mushrooms, the others being the Spikerock, the Grave Buster, and the Gold Magnet.
 * A cardboard Chomper doesn't seem to chew, but it still swallows after a while.
 * The Chomper and the Grave Buster are the only plants that can eat (not including the Imitater versions).
 * The Chomper, however, is the only plant that can eat a zombie.
 * In the Plants vs. Zombies website it says 175 sun instead in 150, because in game 150 not 175.
 * The Chomper, Squash, and Tangle Kelp is the only instant kills that are not explosive.
 * The Chomper and the Tangle Kelp are the only instant kill that cannot affect more than one zombie at a time.
 * The Chomper's Almanac entry states that it was going to be a movie star. Its explicit reference to the Little Shop of Horrors movie may be due to the fact that it resembles Audrey II, the carnivorous monster plant from that movie.
 * On the DS version, the Chomper's Almanac entry replaces "The Little Shop of Horrors" with "Hollywood." This may be because PopCap didn't have enough room on the screen for its full entry.
 * In addition to the aforementioned Audrey II, the Chomper's design bears a resemblance to the Piranha Plant in the Mario series.
 * The Chomper on the start-up screen for Plants vs. Zombies doesn't have spikes on the back of its head, making it look even more similar to a purple Piranha Plant. It is one of the plants shown at the loading screen, the others being Sunflower, Peashooter, Repeater, Wall-nut, Tall-nut, and Cactus.
 * In the art cover of the Plants vs Zombies Original Soundtrack, Chomper is visible singing along with the Squash and Sun-shroom. This version has three spikes on its head, while the in-game Chomper has four.
 * When the Bungee Zombie is place on Chomper, it's not eating and steals an Chomper plant. This may because in Almanac Entry steals a plant in Bungee Zombie's entry.
 * It's rather easy to beat an ordinary Day, Pool or Roof level with only Chompers and (at the beginning) Potato Mines as offensive plants. Bungee Blitz/5-5 is also an example of a Chomper-leading level, but as the zombies don't need to walk across the roof in this level, it's a bit harder than regular levels.
 * The Chomper has its sharp teeth, like sharks and other an animals with sharp teeth.
 * You can plant Chomper in a Pumpkin to protect eating and chomp him.
 * It can be also in the pool, to eating Ducky Tube Zombie. You can also plant Chompers in the Day, Night, and Roof to be eaten a Bungee Zombie.
 * If eats a zombie, it hears a chomp sound. Just like eating a food to chomp.