Acid Pit

You create an extra-dimensional hole with a depth of 10 feet per two caster levels (maximum 100 feet). At the bottom of the pit is a pool of acid. 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 on a square 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 pet 10 feet), plus 2d6 points of acid damage from per round spent in the pit. The walls of the pit are quite slippery: to climb them, a creature need a successful Athletics or Mobility skill check with a DC of 30. 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.