Piercing Thorns. If a bloodpetal hits a creature with both slam attacks on its turn, it deals additional 7 (2d6) piercing damage to that creature. If the opponent or the bloodpetal is grappled, the bloodpetal deals this damage automatically at the start of its turn as long as the grapple persists.
Thorn Shield. Any creature that hits a bloodpetal with handheld weapons or natural weapons takes 4 (1d6+1) piercing damage from the bloodpetal's thorns unless the weapon has a Reach property.
Multiattack. A bloodpetal makes two slam attacks and uses its poison action.
Slam. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 6(1d6 + 3) bludgeoning damage.
Poison. A bloodpetal targets one creature within 5 ft. of it that it can see. That target must make a DC 14 Constitution saving throw. On a failed saving throw the target becomes poisoned for 24 hours. While the target is poisoned in this way, whenever it makes a Dexterity or Constitution ability check or saving throw, it substracts -1d4 from the roll.