Clamshell

Clam Shell is a shield and weapon in the Chinese version of Plants vs. Zombies 2: It's About Time. It is used by the Clamshell Zombie when it encounters a plant. It has the toughness of the Knight Helm. The clam shell will close on any plant within range, killing it instantly.

Trivia

 * This is the only aquatic weapon used by zombies.