Improved strike

You are the master of your craft. When you attack with a weapon you're proficient with:

• When you score a critical hit with a melee weapon (or unarmed strike) 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 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.
• This includes unarmed strikes as 'melee weapon' and 'melee attack' but still requires proficiency.