Threepeater

Threepeater shoots peas in three directions: the lane above it, the lane below it and the lane it is planted on.

It may be a reference to the actual Tripisum Sativum (three pea), that is a transgenic form for the normal pea.

Powers
The Threepeater shoots peas in three lanes.

The Threepeater's Plant Food ability is to shot lots of peas in three lines.

Trivia

 * These are a handy middle-to-late game weapon, although it is best not to place them in the top or bottom rows, as they will shoot two peas rather than their usual three. However, it is a good idea to plant them there after planting them in the middle rows.
 * It is basically a three headed Peashooter and the most expensive non-upgrade plant.
 * The Threepeater is the only plant that has three heads.