Butter is one of the two projectiles launched by Kernel-pults (the other being kernels). It will stun most zombies in any game it appears, as well as deal 40 DPS to the zombie it hits, although it is still launched slower than peas from a Peashooter like any other lobbed-shot plant. However, it is launched much less often than kernels, as it has only a 25% chance of being lobbed. Butter will paralyze zombies for a longer time in Plants vs. Zombies 2.
When a zombie is hit by butter with the exception of Zombonis, Pogo Zombies (that still have their pogo stick), Dr. Zomboss and any vaulting zombie that vaults at the right timing, it is temporarily immobilized. After five seconds, the butter will disappear from the zombie's head. Also in any Co-op Mode on the console versions, the player can manually butter a zombie by pressing the button (Xbox 360) or button (PlayStation 3), although this butter does not do any damage to zombies.
In the mini-game Buttered Popcorn, which is exclusive to the iPad and Android versions of Plants vs. Zombies, the player has the ability to freeze a zombie in their tracks with butter by simply tapping their head. Because the only offensive plants in this mini-game are four Cob Cannons, it is crucial to paralyze the zombies with butter so that the zombies do not eat the Cob Cannons.
In this game, the immobilizing time is much longer (eight seconds). A butter stick can instantly kill a Seagull Zombie, Zombie Parrot, Pelican Zombie, or Bug Zombie. It will also force any flying Dodo Rider Zombies to land. Butter can also be applied using the butter zombie in Vasebreaker.
The butter returns once more in this game as Kernel-Pult's secondary projectile, with its stunning time reverted to five seconds like in the first game. Levelling up Kernel-Pult's Tacobility slightly increases the duration of butter and his chance to toss them. Other plants like Buttercup and Butternut Squash also make use of butter although it does not deal any damage to zombies.
- In the music video "Zombies on Your Lawn," there is a Zombie that has butter on its head.
- Explorer Zombie and Torchlight Zombie cannot burn plants while butter is on its head.
- The Kernel-pult launches this projectile, although butter does not grow from corn, although some people put butter on their corn cob. However the other projectile Kernel-pult launches grows from corn, which is kernels that make up a corn cob.