In Plants vs. Zombies 2, the plant that fires a laser beam through every zombie in its lane is the Laser Bean. It attacks by projecting a beam from its face, allowing it to damage multiple zombies at once rather than stopping at the first target.
Laser Bean is especially useful when zombies are grouped together. Its beam passes through a lane and can hit several enemies, making it a strong answer to dense waves and formations in which ordinary projectiles would be absorbed by the front zombie. This lane-wide attack is the plant’s defining feature and explains its name.
A common mix-up is confusing Laser Bean with Electric Blueberry or Lightning Reed. Electric Blueberry randomly zaps a zombie, while Lightning Reed fires chain lightning that can jump between nearby targets. Laser Bean is different: its attack is a straight, continuous lane effect. In Plants vs. Zombies 2, it is associated with Far Future content and can also receive a stronger beam attack when powered by Plant Food.