Cryptozombologist

Cryptozombologist is an achievement unlockable on the Xbox Live Arcade, iOS, and the Steam version of Plants vs. Zombies. It has the same requirement as Zombologist. This achievement is unlocked by encountering the Zombie Yeti, which is found in Level 4-10 after beating Adventure Mode for the first time.

Steam icon

Zombie Yeti in action on Level 4-10 replayed

Trivia

The word "Cryptozombologist" comes from cryptozoology, meaning the study as cryptids, and zombies.
It is called Zombologist in the iOS, Android, and Game of the Year versions (excluding the Steam version).
In Game of The Year edition, it says "Discover the Yeti Zombie" instead of "The Top Secret Zombie." Technically, this is so because it is a completely different achievement; it is also called Zombologist instead of Cryptozombologist, but in the Steam version, the description is the same as Zombologist.
If the player uses the I, Zombie hack and places a Zombie Yeti, the achievement will not be obtained.

Area Specific
Day	Good Morning
Night	No Fungus Among Us · Photosensitive
Pool	Don't Drink the Water** · Don't Pea in the Pool · Pool's Closed
Fog	Blind Faith · Cryptozombologist · Nebulaphile · Zombologist
Roof	Grounded · Unsiege Mentality**

Mode Specific
Mini-games	Attention Deficit · Beyond the Grave · Chilli Free · Diamond Beghouler · Lucky Spin · Roll Some Heads · Shooting Star · Sproing! Sproing! · Wall-Not Attack · ZFF's 4 Evr
Puzzle Mode	Better Off Dead · China Shop · Gotcha! · Hammer Time! · I, Win · Smashing! · Still Standing · The Stuff of Legends · Think Hard · Where the Sun Don't Shine · Sol Invictus
Survival Mode	Alive and Planting · Immortal* · Tough Beans
Zen Garden	Enlightened · Greenfingers · Greenhouser** · Towering Wisdom

* means the achievement is PC-exclusive. means the achievement is handheld-exclusive. * means the achievement no longer exists.

<poll> How would you rate Cryptozombologist's difficulty? Very hard Hard Somewhat hard Medium Somewhat easy Easy Very easy </poll>