Polearm Master

You can keep your enemies at bay with reach weapons. You gain the following benefits:

• When you take the attack action and attack with only a Glaive, Halberd, Quarterstaff or Spear, you can use a Bonus Action to make a melee attack with the opposite end of the weapon. The weapon's damage die for this attack is a 1d4, and the attack deals bludgeoning damage. This attack uses the same ability modifier as the primary attack.
• While you are wielding a Glaive, Halberd, Pike, Quarterstaff or Spear, other creatures provoke an opportunity attack from you when they enter the reach you have with that weapon.