Not Baaad

Difficulty: Hard-Extremely Hard

Not Baaad is an achievement in Plants vs. Zombies 2: It's About Time. It is achieved by completing a level with Wizard Zombies and no plants turned into sheep. It is worth 1,000 XP on Android devices.

Strategies
It is very difficult to get this achievement in normal levels of Dark Ages. It is recommend to get this achievement on the first level of Arthur's Challenge, because only a few Wizard Zombies will come. Then use instant kills like Cherry Bomb to dispose of them quickly so that they do not transform any of your plants. You can also use Iceberg Lettuces (also when boosted) to freeze Wizard Zombies and then the Cherry Bomb (along with its Imitater version) as a one-use combo to get this achievement on the first level of Arthur's Challenge.

Trivia

 * The name of this achievement is a pun, as a sheep's sound is usually referenced to as "Baaa!".
 * A-noob-us and Mutiny have the similar objectives.