Design change: The color of the laser it fires has been changed from red to blue.
Update 1.16.10
Rarity change: Rare → Super-Rare
Update 1.30.4
▲ Strength change: 4 → 5
▲ Health change: 6 → 7
Strategies
With
Laser Bean is a 6-sun 5/7 plant, which isn't very astounding. But thanks to its Strikethrough trait, you can use it as a finisher or late-game card, where it can alarm your opponent to react to a plant that always (barring Super-Blocks) chips a quarter of their maximum health per turn. It is a very reasonable 'big drop' in the mid-to-late game, because of its stats and the ability to pressure your opponent, and it is also a solid card in many 'mid-range' Solar decks which aim to drop one big card every turn.
Each hero has their own unique strategy to use with it. Wall-Knight can use Pecanolith to ensure that it does 7 damage instead of 5 (it will weaken as it takes damage, however), Solar Flare can increase its base strength, and Chompzilla can use boosting cards like Grow-Shroom on it or use Umbrella Leaf to give it Untrickable. Rose could use a combination of freezing and bouncing effects to repel any zombie in the way, as it is too costly for any meaningful bean synergy.
Since it costs a huge amount of sun to play, try to use ramp decks if you intend to play it. Laser Bean is also vulnerable to removal and doesn't have any immediate effect on the field nor useful synergies, so you may be tempted to switch him out with something else.
Against
Laser Bean combines extreme strength and health with the dangerous strikethrough trait. It can be harmful if you leave it alone for too long, though thankfully its raw stats are really just everything it offers.
Try to play an instant kill like Rocket Science to get rid of it immediately or abuse the deadly trait to your advantage, as 7 health can be difficult to chip down otherwise. You can use Exploding Fruitcake to destroy this card for only 2 brains to gain a massive tempo advantage over your opponent.
Gallery
Plants vs. Zombies Wiki has a gallery for Laser Bean.