Rule 34 Dev - 1boy 2020s 2021 2d artist_name artist_signature ass black_background black_hair commission dark_background digital_media hair hair_over_one_eye hands_on_hips humanoid humanoid_robot male male_only mettaton mettaton_ex multiple_views nsfwgarbagedump nude nude_male pink_eyes robot robot_boy robot_humanoid simple_background solo_male undertale undertale_(series) video_game_character video_games|1013499