Cantrip Void

You create a magical void inside a glass orb that you are holding in your hand. For the duration of the spell, and as long as you are holding the orb, you can store cantrips cast by your self inside the orb, making it stronger.

For each cantrip you cast, add the damage dice and a single quality of said cantrip, which could be range, damage type, saving throw effects or other similar effects. For example, you can add the Shoking Grasp quality that allows you to roll with advantage against targets wearing armor made of metal. You can cast a single cantrip more than once, adding the damage dice and a single different effect each time.

For each cantrip added this way, the orb glows with bright light and makes a buzzing sound, both effects for an additional 5 ft each time. As flavor, the light represents the damage type by it´s color. If no damage type is chosen, then deals Force type damage, and emits a clear white light.

At any time before the spell ends, you can use your reaction to attack a single creature that you can see, throwing or smashing the orb accordingly.  Make a spell attack roll for the corresponding range that you chose for the orb. If no range was chosen, the orb can only be used at melee range. For each cantrip added to the orb, take a +1 to your spell attack roll, as the orb gets stronger with more magic.

On a hit, the target receives all of the damage dice at once, and gets to make a single saving throw roll against all of the effects added to the orb. If the effects added have the "on a save take no damage" condition, this spell surpasses that dealing the damage anyway, but the side effects miss the target.

If you loose concentration at any point before releasing the orb or if you run out of time and don't use it before the spell ends, you get hurt by all the cantrips at once, and you get to make the saving throw against possible side effects with advantage.

You can choose to extend this spell duration by casting it again, adding an additional minute each time.

Side Notes: This spell can be counter spelled when the void is created, not when the orb it is used for making the attack roll. It is also immune to the Dispel Magic effect or similar auras, since the void is protected by the special orb used as material.