Gadget Scientist is a premiumrarezombiecard in Plants vs. Zombies Heroes, and a member of the Brainy class. He costs 5 to play, and has 2/3. He has no traits, and his ability makes every science zombie on the field do a bonus attack when he is played, including him.
By himself, this is a weak zombie that only does one bonus attack, and is not worth the expensive cost. However, if you have other science zombies on the field, Gadget Scientist can wreck some havoc against the opponent. The Brainy class has many science zombies, some that benefit from attacking again such as Kite Flyer or Zombot Drone Engineer, or just strong attackers like Copter Commando or Portal Technician. The Sneaky, Crazy, and Beastly classes also have some powerful science zombies like Template:PvZHLink, Template:PvZHLink, Disco-Tron 3000, and Zombot 1000. Zombot Sharktronic Sub can allow a lawn to be cleared and the Zombot Sharktronic Sub to be boosted should the lawn be mauled with science zombies against many plants.
Mostly Copter Commando and Gadget Scientist mainly make a great team, because you can play Hail-a-Copter to summon Copter Commando first in an empty lane during the trick phrase, doing 6 damage to the plant hero. Then at the next turn, you can play Gadget Scientist for the Copter Commando to attack again, doing another 6 damage to the plant hero. This works really well to finish the plant hero at least turn 6 or above.
You can take advantage of Gadget Scientist's ability by giving traits such as Deadlyor Frenzy to the science zombies. The bonus attack along with the traits are a good combination as the traits will positively affect the science zombies that are triggered by Gadget Scientist's ability.
Against
There's nothing you can do about his special ability, but the zombie himself is pretty weak, many plants can destroy this zombie easily. You do need to be careful if there are other science zombies in the board as Gadget Scientist allows all science zombies to do bonus attacks. In that case, you want to try to destroy as many science zombies as possible before Gadget Scientist is played so that it becomes useless.
However, his weapon looks more alike with Space Cadet's weapon.
The description mentions the Mad Chemist, another zombie card in this game as both has the same colored hair, although a slight different hair style.
When Gadget Scientist is played, if the plant hero blocks one of the bonus attacks and gets Transmogrify, and then uses it on another science zombie, the spawned zombie would still do a bonus attack even if that zombie does not belong to the science tribe.
Brainy class. He costs 5
to play, and has 2
/3
. He has no traits, and his ability makes every science zombie on the field do a bonus attack when he is played, including him.
Deadly or 
Frenzy to the science zombies. The bonus attack along with the traits are a good combination as the traits will positively affect the science zombies that are triggered by Gadget Scientist's ability.
Brainy
Crazy
Hearty
Sneaky