Torchwood

The Torchwood lights regular peas on fire when they pass through its flame, adding extra damage and an additional attack to enemies that are near. When planted during the Fog levels, it clears the fog around it for approximately one-and-a-quarter squares. The only other plant that can eliminate fog until eaten is the Plantern.
Although there is a flowering plant family known as Torchwood (Burseraceae), which includes frankincense and myrrh, the name may also be a reference to the eponymous organization in the Doctor Who spin-off series.

Place Torchwoods in any lane in front of any plant that shoots peas to turn the peas into flaming projectiles that do double the normal damage. It also adds splash damage which deals a normal pea's damage to all nearby zombies. However, if a frozen pea passes through it, it will melt, becoming a normal pea that does normal damage. Any zombie with a shield will prevent the splash effect. A flaming pea also defrosts zombies, so using them in combination with Ice-shrooms, Winter melons and Snow peas is not reccommended.