Board Thread:General Discussion/@comment-31483225-20170323191947/@comment-30737249-20180312163343

Undertalelover445 wrote: I say that due to Genocide-exclusive bosses having a pattern in HP (Undyne the Undying has 20,000 HP, Mettaton NEO has 30,000 HP) Sans would have 40,000 HP. However, 999,999,999 > 40,000 HP, so everyone thinks he has 1 HP. I'm getting tired of saying this.

Datamining has found Sans indeed does only have 1 HP. HP is a greay-area stat, so the in-game values technically count.

Also, Undyne the Undying has 23 000, so Sans would have 37 000, not 40 000.