Eldritch Smite
Prerequisites Level 5, pact of the blade|xphb
Once per turn when you hit a creature with your pact weapon, you can expend a Pact Magic spell slot to deal an extra dice:1d8|noform|noparens|avg (1d8) Force damage to the target, plus another dice:1d8|noform|noparens|avg (1d8) per level of the spell slot, and you can give the target the Prone condition if it is Huge or smaller.
Sources
Player’s Handbook (2024) p. 155