Corpse Blossom

Choose one creature within range. The target must make a Constitution saving throw. On a failed save, it takes 4d8 Poison damage and has the Poisoned condition for the duration. On a successful save, it takes half as much damage only. At the start of each turn of a creature Poisoned by this spell, that creature takes 2d8 Poison damage. At the end of each of its turns, it repeats the saving throw, ending the spell on itself on a success.

If a creature dies while Poisoned by this spell, its corpse erupts in a shower of sickly green flowers. Each other creature in a 10-foot Emanation originating from the corpse must make a Constitution saving throw. On a failed save, a creature takes 2d8 Poison damage and has the Poisoned condition until the end of its next turn. On a successful save, it takes half as much damage only. A creature that dies while Poisoned by one of these eruptions also blossoms in this way. A creature can take damage from only one such eruption during a turn.

Using a Higher-Level Spell Slot. The initial damage increases by 1d8 for each spell slot level above 3.