Board Thread:General Discussion/@comment-34404946-20180120072411/@comment-34447632-20180124210232

If I recall it said Sans 1 atk 1 DEF The easiest enemy Can only deal 1 damage.

With stats like that It is probably not just coded as 1 for laziness, It is probably 1 HP as a actual character trait, Rather than a number you would not see without hacking.