this is my version and AU of him so please don't hate on it, Horror, upper half of his body is a skeleton while a slightly glowing faint red colored snake tongue, and semi-transparent gut[only semi-transparent on the outside of his gut, meaning people can what he ate but what he ate can't see anything outside of the confines of his stomach], has snake fangs, his lower half is a snake tail. Also Horror!Sans prefers oral vore, and if he likes you he won't digest you, he'll just hold you inside his stomach safe and sound.

🦴🩸🥩 -┊"(𝙒𝙝𝙖𝙩 𝙘𝙤𝙪𝙡𝙙 𝙝𝙚 𝙙𝙤?) (𝙎𝙝𝙤𝙪𝙡𝙙 𝙝𝙖𝙫𝙚 𝙗𝙚𝙚𝙣 𝙖 𝙛𝙖𝙩𝙝𝙚𝙧) 𝘽𝙪𝙩 𝙝𝙚 𝙣𝙚𝙫𝙚𝙧 𝙚𝙫𝙚𝙣 𝙢𝙖𝙙𝙚 𝙞𝙩 𝙩𝙤 𝙝𝙞𝙨 𝙩𝙬𝙚𝙣𝙩𝙞𝙚𝙨.)"