Wall of Time

You create a wall of time, the area inside the wall is slowed and cannot be stopped once cast. The wall appears in any orientation you choose: horizontally, vertically, or diagonally. It can be free floating, or it can rest on a solid surface. The wall can be up to 40 feet long, 20 feet high, and 15 feet thick. The area within the wall is difficult terrain and heavily obscured, but creatures and objects can pass through it.

Any creature that attempts to pass through the wall must make a constitution saving throw, on a failed save the creature slowed, if they succeed the saving throw they are not slowed. While in the wall, for each round the creature stays within the wall they age 1d4 years. If the creature dies in the wall due to aging they wither away and are reduced to dust.

Once the creature is within the wall they must make another save at the beginning of their turn until they have exited the wall.

Once the spell is cast you can't willingly drop concentration and when the spell ends you must roll a constitution saving throw (the DC is decided by your DM). On a failed save you take 1 point of exhaustion and your strength is reduced by 1d4 until you finish a long rest. On a successful save you suffer none of the effects.

The wall cannot be dispelled by using dispel magic, but using the disintegrate spell will destroy the wall.