Plantern is an unlockable plant in Plants vs. Zombies as an environment modifier whose purpose is to clear fog which obscures the player’s vision.
Plantern is obtained in the Fog area, specifically after beating the first level, and will illuminate and disperse a large area of fog (5×7), allowing the player to see approaching zombies and their own defense within the cleared radius. He can be planted anywhere, but is only used for his real purpose in the Fog and Vasebreaker levels. Technically, like the Grave Buster, the Plantern is not actually a Night plant. Because he is not a mushroom, he does not need to be planted in the Mushroom Garden to grow.
The only purpose of Plantern is to illuminate areas of Fog in the fog levels and It’s Raining Seeds. Plant him within the foggy area on the right side of the screen to reveal the enemy. If Planterns are planted one square into the foggy area in the rows on either side of the Pool, all of the fog will disappear aside from some scraps of it in the corners of the screen.
In Vasebreaker, he is used to reveal what the vases contain within a 3×3 range.
He is a more easy-to-use and a more sun-saving alternative than the Blover. The latter however can be used in a harder but more practical way.