Eldricht Strike

Your body crackles with energy as you strike out at a creature within 5 feet. Make a melee spell attack against the target. On a hit, the target takes 2d8 force damage, is knocked back 10 feet, and must pass a Con save or is also knocked prone.

At higher levels, attack damage is increased by 1d8, and the force of your strike is amplified: 

• 3d8 at 5th level, and any creatures within 30 ft in a straight line in front of the player character are knocked back 10 feet. Ranged creatures take no damage from the strike.
• 4d8 at 11th level, and any creatures within 30 ft in a straight line in front of the player character are knocked back 10 feet, and must pass a Con save or are also knocked prone. Ranged creatures take no damage from the strike.
• 5d8 at 17th level, and any creatures within 30 ft in a straight line in front of the player character, including the target, are knocked back 10 feet, and must pass a Con save with disadvantage or are also knocked prone. Ranged creatures now take 1d4 force damage on failed Con save.