The Scientist is the first human you encounter in Zombotron 2. He is responsible for making the Robomachine which is the final boss in Zombotron 2. He also becomes a mini boss after you defeat the Robomachine, though he is easy to defeat.
When the Hero first encounters the Scientist, he is surprised, remarking the Hero doesn't look like a zombie or bio-bot. He asks the Hero to clean out all the spiders in his storehouse and in return, he will show the Hero to the Space Base.
After defeating the spider boss, the Scientist thanks the Hero and gives him the keys to the Zombomobile.
In the last level of the game, after defeating the Robomachine, the scientist appears carrying a machine gun, stating that "years of work have been destroyed" and that he suspected the Hero would be "nothing but trouble," even though the Hero had cleaned out his storehouse. After calling him names and telling him to die, the Scientist starts firing his machine gun at the Hero, but he is easily killed by the Hero.
Just before his demise, two mutants appear talking about the Hero, one comforting the other saying,"Even if he does [get here], the professor's robot will strike him down."
On level six, when you exit the storehouse, you can push him out of the bubble zone by going back then running into him. If you repeat this process until he is past the exit door, go ahead to trigger the door closing and the guns returning to normal. If you kill the professor at that point by shooting him a couple times, he will just disappear as there is no death animation present for that character, who is most likely just using the scientist's model, but is a prop.