SRD:Up the Walls
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Up the Walls [Psionic]
You can run on walls for brief distances.
While you are psionically focused, you can take part of one of your move actions to traverse a wall or other relatively smooth vertical surface if you begin and end your move on a horizontal surface. The height you can achieve on the wall is limited only by this movement restriction. If you do not end your move on a horizontal surface, you fall prone, taking falling damage as appropriate for your distance above the ground. Treat the wall as a normal floor for the purpose of measuring your movement. Passing from floor to wall or wall to floor costs no movement; you can change surfaces freely. Opponents on the ground can make attacks of opportunity as you move up the wall.
You can take other move actions in conjunction with moving along a wall. For instance, the Spring Attack feat allows you to make an attack from the wall against a foe standing on the ground who is within the area you threaten; however, if you are somehow prevented from completing your move, you fall. Likewise, you could tumble along the wall to avoid attacks of opportunity.