Zombifier

This is a very tough zombie that can turn your plants into zombies.

Stats
HP: 35

Damage: Technically none, but turns plants into zombies.

Cost in Zombie Mode: 500 Brains

Speed: Normal

Strategy
Use instant kills, but plant the instant kills BEHIND it, or they will be turned into zombies. High firepower will also take it out. See here for information about its zombification.