Abyssal Rose Field

you bring the small petal/dust in your hand to life and you kneel while you hold it above you. a giant flower will slowly bloom constantly releasing damaging petals (8d4 Necrotic damage) for every action, movement, bonus action, or if a creature starts or ends its turn within the spells range. on the 5th round the giant flower and all the little petals will burst into a black flame making anything in range except the caster take (10d10 Necrotic damage).