Expeditious Construction

You create a low wall or other simple structure of packed earth or loose stone measuring 3 feet thick, 3 feet tall, and 10 feet long per 3 caster levels you possess (minimum 10 feet). Each square of the structure can appear only in unoccupied spaces atop earthen or stone surfaces able to support it. The wall grants cover as per a low wall and can be climbed with a successful DC 5 Climb check.

Large and larger creatures don't need to attempt a Climb check to climb over it.

At your discretion, you can make the structure half as long but thicker by forming it into a berm consisting of a steep slope on each side. Characters moving uphill (to an adjacent square of higher elevation) must spend 2 squares of movement to enter a square of steep slope. Characters running or charging downhill (moving to an adjacent square of lower elevation) must attempt a DC 10 Acrobatics check upon entering the first steep slope square. Mounted characters attempt a DC 10 Ride check instead. Characters who fail this check stumble and must end their movement 1d2 × 5 feet later. Characters who fail by 5 or more fall prone in the square where they end their movement. A steep slope increases the DC of Acrobatics checks by 2.