Spiked Pit

You create an extradimensional hole with a depth of 10 feet per two caster levels (maximum 50 feet). The pit is lined with wickedly sharp spikes along its bottom and walls. Any large or smaller creature standing in the area where you first conjured the pit must make a Reflex saving throw to jump to safety in the nearest open space. In addition, the edges of the pit are sloped, and any creature ending its turn in a space adjacent to the pit must make a Reflex saving throw with a +2 bonus to avoid falling into it. Creatures subjected to an effect intended to push them into the pit (such as bull rush) do not get a saving throw to avoid falling in if they are affected by the pushing effect. Creatures who fall into the pit take falling damage as normal (1d6 bludgeoning damage per 10 feet), plus 2d6 points of piercing damage from spikes. To climb the pit's coarse stone walls, a creature needs a successful Athletics or Mobility skill check with a DC of 25. When the duration of the spell ends, creatures within the hole rise up with the bottom of the pit until they are standing on the surface over the course of a single round.