What is the last incorrect word in the text

Mad scientists are very smert. They often conduct experimants that can be dangerous.  Mad scientists usally use their knowledge for bad things. A mad scientist might be an inventer or a potion brewer. Both these jobs can be used for good or bad.  Mad scientists usually have a lab wear they test out their inventions, experiments and technology. Mad scientists are often crazy or insane but that doesn’t step them from making cool discoveries.