Void Mass

You release the ink used in the spell’s casting and expand it into a black mass that channels the chilling darkness of the void. The mass is a 10-foot radius sphere which you centered on a point within range when you cast the spell. The sphere spreads around corners, and has the following properties:

• The area is magical darkness. A creature with darkvision can’t see through the sphere’s darkness, and nonmagical light can’t illuminate it.
• No sound can be created within or pass through the sphere. Any creature or object entirely inside the sphere is immune to thunder damage, and creatures are deafened while entirely inside it. Casting a spell that includes a verbal component is impossible there.
• A creature wholly inside the sphere can not breathe.

As an action on each of your turns, you can move the sphere up to 30 feet, or increase the sphere’s radius by 5 feet.