Warp Shield

Swirling purple energy fills a 20-foot cube centered on a point you can see within range. When you cast this spell, choose which type of field you create from the following:

•    Protect: The energy protects creatures within the field; creatures within the cube are treated as having resistance to all types of damage. When a creature starts its turn within the cube, it gains temporary hit points equal to 1d6 + your spellcasting ability modifier, replacing any other temporary hit points granted by this spell. These temporary hit points are lost when the spell ends or when the creature leaves the spell's area of effect.
•    Expose: The energy exposes creatures within the field; creatures within the cube cannot benefit from damage resistances. When a creature starts its turn within the cube, it must succeed a Constitution saving throw or take 1d6 + your spellcasting ability modifier Necrotic damage.

The spell ends early if you cast it again or if you dismiss it, no action required. The effects of multiple Warp Shield spells do not stack, and only the newest effect applies. A creature must be fully within the cube for the spell to affect it.