D&Dtools1

Black, glistening thorns emerge from your skin, causing you no damage but endangering those who attack you in melee.
Any creature grappling with you or striking you with handheld weapons or natural weapons takes 1d6 + your Strength bonus in piercing damage from the thorns that protect you.
Weapons with exceptional reach, such as longspears, do not endanger their users in this way.
You can't use the thorns yourself to attack; they're effective only when someone attacks you.
Furthermore, a scratch from the thorns is sufficient to deliver a dose of poison to your attacker.
Any creature grappling you is exposed to the poison each round at the start of your turn.
The poison from the thorns deals 1d4 points of temporary Strength damage immediately and another 1d4 points of temporary Strength damage 1 minute later.
Each instance of damage can be negated by a successful Fortitude save (DC 10 + 1/2 your caster level + your Wisdom modifier).
Material Component: A dried black rose.