Eldritch Domain Expansion

Eldritch energy radiates from you, creating a 30ft radius opaque sphere centered on your location. If the sphere cuts through a creature's space when it appears, the creature is pushed to one side of the sphere (your choice). The area within the sphere becomes an interdimensional space that reflects the domain of your patron or the circumstances of your pact. For the duration, each non-hostile creature in the area (including you) has advantage on attack rolls and each attack deals an extra 1d4 necrotic damage. 

Nothing can physically pass through the sphere. Each 5ft section of the sphere is an object that can be damaged and thus breached. Each section has AC 16 and 10 Hit Points per Warlock level. Reducing a section to 0 Hit Points destroys it. Once a section is destroyed, the spell remains but the benefits received by non-hostile creatures end. The sphere cannot be dispelled by Dispel Magic.