Jsk Feats:Great Weaponmaster

You've learned to put the weight of a weapon to your advantage, letting its momentum empower your strikes. You gain the following benefits:
 * 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 penalty to the attack roll. If the attack hits, the attack deals additional damage. Use the table below to calculate both the penalty and the bonus damage.