Once per turn, creatures provoke an opportunity attack from you when they enter your weapon’s reach. Additionally, if you are wielding a melee weapon in one hand and no other weapons or shields, you gain a +1 bonus to attack and damage rolls with that weapon and a +1 bonus to Defense.

If you are 6th level or higher, when you hit a creature with an opportunity attack, it loses its remaining movement, though it can dash to move further.