Great Weapon Master

* On your turn, when you score a critical hit with a melee weapon or reduce a creature to 0 hit points with one, you can make one melee weapon attack as a bonus action.
* Before you make a melee attack with a heavy weapon that you are proficient with, you can choose to take a - 5 penalty to the attack roll. If the attack hits, you add +10 to the attack’s damage.
Appears In : 5e Players Handbook