FURVERT!

animal_genitalia animal_penis balls body_size_growth cosmonaut cutie_mark digital_media_(artwork)drawnheart equid equine equine_genitalia equine_penis fan_character feral genitals glowing glowing_horn greyscale hasbro hi_res hooves horn horse inside macro male mammal monochrome my_little_pony mythological_creature mythological_equine mythology penis pony size_transformation solo transformation unicorn