Argento Soma

In the year 2059, the earth has been plagued by aliens for several years. In an effort to learn more about these aliens, Dr. Noguchi and his assistants Maki Agata and Takuto Kaneshiro try to revive the professor's experiment, a large Bio-Mechanical alien named Frank. During this process the alien comes to 'life' and the lab is subsequently destroyed leaving Takuto the only survivor and the alien disappearing into the wilderness. (myanimelist.net)