He has a white mustache, beard and swirly glasses. In Wario Land 3 he wears a dome helmet surrounded by glass and wears a lab coat befitting a scientist, while in Wario Land 4 he reverts back to the bald head that is shaped like a butt and is a wearing brown coat and pants befitting an archaeologist.
In Wario Land 3 & Dr. Mario 64 his Japanese name is Mad Stein (マッドシタイン) while in Kaeru no Tame ni Kane wa Naru & Wario Land 4 it's Arewo Shitain-hakase (アレヲ・シタイン博士).