The Winter Melon
They are awesome. Despite my name (Melon-pult) I am still a Winter Melon fan. Not only are they strong, but they slow zombies down. They do 4 peas worth of damage along with splash damage. The splash also does 2 peas worth of damage to nearby zombies while also freezing them.
They are one of the most powerful plants along with the Cob Cannon and Gloom-shroom, But unlike the Cob Cannon, they fire automatically, and unlike the Gloom-shroom, it has longer range. It is also used frequently in Survival:Endless like this one:I think they should be used in almost every Survival:Endless builds. I prefer them over Peashooters in Survival: Endless because it freezes groups of zombies. Not only that but they also do heavy damage to Zombies. Gargantuars and Giga Gargantuar appear very frequently in Survival: Endless, but Winter Melons weaken them significantly.
Just to sum things up, Winter Melons are awesome. End of story.