Xbooru - 1girl 2020s 2021 2d 2d (artwork) animated skeleton blue blush blue body blue breasts blush breasts cleavage digital media (artwork) ectobody ectobreasts female female only female sans genderswap genderswap (mtf) hand behind head looking at viewer monster one eye closed rule 63 sans sans (undertale) siiversinss simple background skeleton smiling smiling at viewer solo solo female undead undertale undertale (series) upper body video games white background wink winking winking at viewer