what if there was a "practice mode" talisman

the idea is that you become immune to damage, but also cannot deal damage. everyone still staggers and stance breaks. you cant pick up items, recieve no runes, cant touch grace, and even if a boss dies, by falling for example, they dont count and will be back when you remove the talisman. when you unequip the talisman you are returned to the last site of grace.