Timeless Boundary [H]

You carve an invisible, wall-like slice through timespace in a point you choose within range. This 'wall' appears in any orientation you choose, as a horizontal or vertical barrier, or at an angle. It can be free floating or resting on a solid surface. You can form it into a hemispherical dome or a sphere with a radius of up to 10 feet, or you can shape a flat surface made up of ten 10ft by 10ft panels. Each panel must be contiguous with another panel. In any form the wall is paper-thin. It lasts for the duration. If the wall cuts through a creature's space when it appears the creature is pushed to one side of the wall (your choice which side).

Magic cannot pass through the wall and it is immune to damage and can't be dispelled by dispel magic. A time stop destroys the wall instantly, however. The wall also extends into the Ethereal Plane, blocking ethereal travel through the wall.

Each time a creature comes into contact with the wall they must make a Charisma saving throw. On a failure the creature is paralyzed as the flow of time for them stops. On a success the creature is able to push through to the other side. A creature frozen in time can repeat the saving throw at the end of each of their turns, ending the condition on a success and being shunted back to the side they were on. Additionally a frozen creature automatically succeeds if they take damage.

Additionally, the strain of having creatures frozen in time makes it harder to focus on the spell. If you are forced to make a Concentration check to maintain the spell, you have a penalty to the roll equal to the number of creatures currently frozen in it.