Zombie Yeti

The Zombie Yeti is a very rare zombie that appears for the first time, after completing Adventure Mode at least once, in the Fog level 4-10 (although, it does not technically contain any fog) in which it is raining and the player can only see when lightning strikes. If the player doesn't kill it in time, it will run away with no reward. However, if it is killed, it will drop five diamonds the first time and four for every other encounter. From that point on, it will appear randomly in other levels (including Survival/Minigames). It cannot be chosen as a zombie, like many others, in Puzzle Mode.

Overview
Absorbs 75 Normal Damage Shots. Appearance Changes after 45 Normal Damage Shots before dying at 75 Normal Damage Shots. Will begin to run away after 12 seconds of being active on lawn. May also begin to run away after reaching the 5th square on lawn

Strategy
Just do whatever you do to kill Buckethead Zombies (besides using Magnet-shrooms). If it tries to run away, it can be stopped by planting a Wall-nut or another defensive plant in its path such as the Pumpkin or Tall nut. If that proves insufficient, plants capable of firing backwards such as the Split Pea or Starfruit can be planted in front of it or an instant kill can be used.

Gold Farming
One recently discovered technique is to repeatedly attempt Level 4-10, the only level in the game where the Zombie Yeti consistently appears. Because the Zombie Yeti, when defeated, yields three diamonds ($3000), the gold farming application is obvious. Do note, however, that unless your version of the game has the Quick Play mode on it (from which you can access Level 4-10 at whim), it is necessary to reach that point in Adventure Mode after defeating it the first time. To be able to keep replaying the level, it is of utmost importance that the player does not collect the money bag at the end of the level, or restarts as soon as the Zombie Yeti is killed.

Trivia

 * So far in the game, the Zombie Yeti is the only zombie that gets seen once you finish the game.
 * The Zombie Yeti and the Gargantuar (and its variant, the Giga-Gargantuar) are the biggest zombies.
 * The Zombie Yeti and the Zombie Bobsled Team are the only zombies that have the word "Zombie" at the start of their names.
 * In the Mini-game Big Trouble Little Zombie the small version of this zombie can appear but it does not drop diamonds.
 * The Yeti Zombie and the Digger Zombie are the only Zombies capable of walking in reverse direction without being hypnotized.
 * It is rare, but possible to see two Zombie Yetis in one level.
 * The Zombie Yeti and the Newspaper Zombie, once its newspaper has dropped, are the only zombies whose eye pupils are red.
 * The Zombie Yeti's almanac entry displays a purple light behind the Zombie Yeti, illuminating its back. This light is found only in this zombie's entry, and no one knows why.
 * The Achievement Cryptozombologist is unlocked by seeing it (Zombologist for Game of the Year, iPhone, iPad or iPod Touch).
 * Along with the Balloon Zombie (while it has its balloon) and Bungee Zombie, the Zombie Yeti does not have a burnt animation. When they are incinerated, their bodies merely turn black and disappear, unlike other zombies.
 * The Zombie Yeti is one of only three zombies (with feet) that don't wear shoes, the other two being the Jack-in-the-Box Zombie and the Imp (This is assuming that Dr. Zomboss and the Catapult Zombie wear shoes).
 * The Zombie Yeti has eight visible teeth, the most compared to other Zombies.
 * The Zombie Yeti, the Zombie Bobsled Team (except for Bobsled Bonanza), the Backup Dancer, Dr. Zomboss, and the Flag Zombie are the only zombies that can appear in a level without being shown in the seed selection.
 * If you hypnotize the Zombie Yeti, it will turn left after biting zombies. While it can lose its head, it does not drop diamonds when hypnotized.
 * It will be able to reach your house when this happens.
 * When you see the Zombie Yeti in Wall-nut Bowling, it takes one hit but still leaves the screen when not killed.
 * The Zombie Yeti costume is available on the Xbox Live Marketplace for 320 Microsoft points.
 * The Zombie Yeti is one of the zombies that have a preferences
 * The Zombie Yeti, the Bungee Zombie, the Digger Zombie (if it reaches the left side of the lawn), and Dr. Zomboss are the only zombies that don't target your house.
 * Although the Zombie Yeti does not appear in the seed selection (with the exception of Level 4-10), it still has a standing animation in the Suburban Almanac.
 * The Zombie Yeti doesn't bend its elbows or knees when walking.
 * The Zombie Yeti, along with the Football Zombie, the Imp, and the old Dancing Zombie are the only zombies with normal feet (excluding the ones that don't step on land).
 * It is possible to encounter the Zombie Yeti more than once in a single Survival level, although it will only appear once every flag (or every two flags if in Survival: Hard or Survival: Endless).
 * The Zombie Yeti, the Balloon Zombie, the Digger Zombie, the Flag Zombie, the Dancing Zombie (and Backup Dancers) the Zombie Bobsled Team, the Dolphin Rider Zombie, the Snorkel Zombie, and the Ducky Tube Zombie are the only zombies not to appear while battling Dr. Zomboss.
 * Zombie Yeti is the only zombie that don't wear clothes.