Eldritch Missile

Once you choose the Pact of the Blade Boon if you know Eldritch Blast you may use this variant of the spell as well. 

You Imbue your Pact Weapon with the energy of your Eldritch Blast and use the magic to hurl the projectile at a target.

A beam of crackling energy and steel streaks toward a creature within range. Make a ranged attack against the target. On a hit, the target takes 1d6 force damage + the damage of your pact weapon if it's a Dagger, Dart, or Light Hammer or 1d4 force damage + the damage of your pact weapon if it's a Trident, Spear, or Handaxe.

When you reach higher levels you learn to imbue more energy into Eldritch Missile: 2d6 or 2d4 of force damage at 5th level, 3d6 or 3d4 at 11th level, and 4d6 or 4d4 at 17th level

If the target dies or you rolled above a 10 on your d20 your pact weapon returns to your hand at the end of your turn. Otherwise, you will need to use a bonus action to recall it on your next turn.