Board Thread:General Discussion/@comment-39394247-20191014002848/@comment-39394247-20191015005219

But at LV 1, even if you are doing a neutral run, you do 30+ damage per hit against monsters with 0 DEF, and no monster does that much damage to you. Datamining might reveal -9999 DEF for Toriel and Papyrus if you are in a genocide run, and -40000 for Mettaton NEO (but the damage is scripted to be 10^6). Undyne the Undying has some nonzero DEF, but not 99.