Lovecraft's Horrors: "Call of the Cthulhu" World.

An immobile, faintly shimmering barrier springs into existence in a 10-foot radius around you and remains for the duration. Any spell of 5th level or lower cast from outside the barrier can't affect creatures or objects within it, even if the spell is cast using a higher level spell slot. Such a spell can target creatures and objects within the barrier, but the spell has no effect on them. Similarly, the area within the barrier is excluded from the areas affected by such spells.