Wall of Skeleton

You touch the ground in front of you and a wall, compleately made of bones and skeletons, emerges from the ground, attacking all creatures within range.

The wall is centered on the point you touch, and stretches 10ft in both directions (for a total length of 25ft) and 10ft up. 
The wall is indistructible and individual skeletons imbedded in the wall cannot be targetted.
Every 5ft of wall,  there is 1 skeleton imbedded in the wall that can attack any enemy within a 5ft range (+4 to hit, dealing 1d6 + 2 damage (shortsword attack)) of the wall.
The skeletons can only attack creatures on the front part of the wall, once they are behind the wall, they cannot be targetted.
All skeletons get oppertunity attacks if the target leaves their range, unless it takes the Disengage action.

Creatures behind the wall get full cover if they are as big or smaller then the wall itself, this counts for both friendly and hostile creatures.

If a creature is occupying any of the spaces the wall would occupy, it jumps 5ft away from where the wall would form, clearing the space for the wall.

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the damage each skeleton deals increases by 1d6 for each slot level above 1st level