You can get weapons such as the Tesla Knife for 25 BP, Epic Bone for 100BP, and a hardcore knife for 500BP. But then you have the Ultra Boss Rush at level 2500, where you fight the AU bosses, The final boss is X Gasterįirst of all, the Infinite Battle Mode, where you can fight an Infinite Undyne the Undying at level 3000 here you get 1 BP (battle point) for every kill, and then you can fight Infinite Sans at 100 BP, where you get 3 BP per kill.

Beginning with the Boss Rush at level 100, which is super easy.