Blossoming Thorn

Make a ranged spell attack against a target creature within range as you hurl a sprouting vine at them. On a hit, the vine latches on to the creature, wrapping around them. You can choose whether to let the vine sprout into thorns instantly, or let it continue to grow. If you cause the vine to sprout instantly, it deals 1d6 piercing damage to the target when it hits, and imposes disadvantage on the target's next attack roll before the end of its next turn as the thorns dig into their arms.

If you wait to sprout the thorns, the vine continues to grow towards the creature's core. At the end of the affected creature's next turn, the vine automatically sprouts into thorns, digging into their armor, dealing 1d10 piercing damage and reducing the target's AC by 1 until the start of their following turn.

 

The damage increases by one die (1d6 or 1d10, depending on which version of the spell you use) when you reach levels 5, 11, and 17.