Amnesia Dust

This blackish grey dust has a cracked pepper taste can be sprinkled over any edible substance. The dust erases memories from the past: anyone eating food treated with this dust must make a DC 15 Wisdom saving throws or loose up to 24 hours of their memories, the time lost is equal to 24hr divided by the number of consumers rounded down. There is enough dust to flavor 3 servings. Additional servings increases the allotted time, i.e. 2 servings = 48hrs and 3 servings = 72hrs