Mad Scienstein

Dr. Arewo Stein (アレヲ・シタイン博士, Arewo Shitain Hakase) is a character who Wario encounters on multiple occasions while exploring the Golden Pyramid in Wario Land 4. He appears as a comically styled, elderly man with a large head, glasses, a mustache, and a beard. He is about 90 years old.

Wario Land 4
Dr. Arewo Stein makes his first appearance in this game during the opening sequence, albeit not in person. A photo of him is shown in the newspaper that reports the discovery of an ancient pyramid. He is a robot engineer and an Honors Professor at the Masakachotto University Engineering Department. He heard the rumors of the Golden Pyramid and set off on his own expedition.

During the game, Wario can usually find the researcher within the various bonus rooms inside the levels. Wario can interact with Dr. Arewo Stein like he does with most other enemies. He can be stunned, picked up, and thrown to break blocks or hit switches that are out of reach. This is commonly required to solve a puzzle in the Puzzle Rooms. Dr. Arewo Stein has a unique sound clip (a loud exclamation of "Oww!") that plays whenever Wario harms him. Unlike most enemies however, none of Wario's attacks are actually lethal to Dr. Arewo Stein. The researcher can sometimes also be found outside of bonus rooms, on the level select screen. After Wario defeats the Golden Diva, Dr. Arewo Stein can be seen escaping the collapsing pyramid alongside Wario and Princess Shokora.

Origin
While his first and only appearance in a Wario Land series game was in Wario Land 4, Dr. Arewo Stein's character actually originated from Kaeru no Tame ni Kane wa Naru (カエルの為に鐘は鳴る, meaning For the Frog the Bell Tolls), a Game Boy game that was released exclusively in Japan. In said game, Dr. Arewo Stein is a member of the supporting cast surrounding the adventure of the Prince of Sablé. Dr. Arewo Stein works as a researcher for an institute on Nantendou Island, providing the protagonist with helpful items such as gloves that increase strength, or a device that can control mammoths. He also appears in the final battle of the game, riding a robot of his own creation, the Tokyo Comic Show Z, which assists in defeating the final boss. Dr. Arewo Stein is said to be a gourmet, and he frowns upon the thought of sharing his food. He is especially stingy when sushi is involved.

Trivia

 * Dr. Arewo Stein has various idle animations. One of them depicts him playing with a Game Boy Advance.
 * He also appears as an obstacle in the mini-game The Wario Hop, and is seen eating a rice ball.