Badberry

Ten berries appear in your hand and are infused with necrotic magic for the duration. A creature can use its action to eat one berry. Eating a berry gives the poisoned condition and reduces the eater's hit point maximum by 1d4 until they finish a long rest. If a second berry is eaten, the eater will eat and drink twice their normal amount for the next 24 hours. These berries appear to be Goodberries, only a DC 20 arcana check will prove otherwise. They are also found to be Badberries under magical inspection.

The berries lose their potency if they have not been consumed within 24 hours of the casting of this spell.