This is one of the easiest costumes I have ever made! We cut a rectangle out of cardboard, stuck it in a backpack and then dressed it. We put a button down shirt on first and stuffed it with paper and grocery bags to give it shape. For the hands I filled rubber gloves and then taped them to the end of the shirt. For the lab coat we used a graduation gown. The sleeves were pinned together just below chin level. The jar was the icing on the cake and people really loved it. We used a plastic jar (cut bottom and back out) so it was easy to just staple to the cardboard. The costume went on just like a normal backpack and the “jacket” was zipped up to hide my sons arms. For details we added a painted oatmeal box as a neck, a necktie, a label to the jar and paper clip art magnifying glass. This costume was super easy for my son to put on and take off by himself, lightweight and a HUGE hit.