Bursting Force

You smack your arms together and release a burst of energy. Each creature in a 20 ft cone in front of you must make a dexterity saving throw or take 2d6 force damage and is either knocked prone or pushed 10ft away from you (your choice, but you can only use this ability if you have taken damage since your last turn). a successful save takes half as much damage and is not pushed. the damage increases by 1d6 for every successful attack against you prior to this action since your last turn.