IDK who is that sans and at this point I don't even want to ask

Description: Sans - ATK10 DEF10 HP 100 - Just another Monster. He's up to something … Be careful. Sans - ATK 99 DEF 0 HP 1 - His DEF dropped to zero, but his attack increased... Be careful. Sans - ATK ??? DEF ??? HP ??? - His ATK and DEF greatly increased … Looks like your attack won't do anything to him. Keep attacking, his body cannot handle this amount of power forever. Sans - ATK 1 DEF 0 HP 0.1 - The easiest enemy … Finish him off!