Eldritch dream

Whenever you roll damage for an eldritch blast you can choose to spend one of your Hit Dice. If you do so, choose between:

add the result of the Hit Dice roll to the damage dealt by the spell or invocation.You can use this ability once per turn.

you can choose to form an explosive sphere. When you cast the cantip in this way, the blast flashes from your finger to a point in range that you can see. At that point, it takes the form of a 10-foot diameter, spherical, explosion of force. Creatures in this sphere must make a Dexterity saving throw, taking 1d10 force damage for each beam of eldritch blast that you are able to cast on a success and half as much on a failure.