Added to the game as the basic zombie of the Brainy class.
Just like all other 1/1 fighters, many other zombies can outperform him. However, if you synergize him with Zombot Drone Engineer and Gadget Scientist since he is in the science tribe, this zombie could work in your favor, but he should typically be used early, and replaced as soon as possible. If you are using Rustbolt, Arm Wrestler might be a better choice.
Anything can counter him due to his lack of abilities and low stats, unless boosting tricks are used on him. Do not consider him as a big threat, unless it snowballs out of control thanks to Zombot Drone Engineer and Gadget Scientist.
Cardboard Robot Zombie's statistics
Cardboard Robot Zombie's statistics after being Conjured by Cosmic Scientist
Cardboard Robot Zombie's statistics after being Transformed into by Transmogrify