Rule 34 Dev - 2010s 2016 2d 2d_(artwork) black_hair digital_media_(artwork) glowing hair hand_cannon humanoid humanoid_robot kissing making_out male male_only mettacest mettaton mettaton_ex mettaton_neo nipepocip robot robot_boy robot_humanoid selfcest square_crossover undertale undertale_(series) video_game_character video_games|1016163