Wall of Fire
Casting Time: 1 standard action
Range: medium (100 ft. + 10 ft./level)
Duration: concentration + 1 round/level
Saving Throw: none
Effect: wall up to 20 ft. long/level or a ring with a radius up to 5 ft.
Spell Resistance: yes
An immobile blazing curtain of opaque, shimmering, violet fire springs into existence. One side of the wall, selected by you, sends forth waves of heat, dealing 2d6 fire damage to creatures within 10 feet and 1d6 fire damage to those beyond 10 feet but within 20 feet. The wall deals this damage when it appears and on your turn each subsequent round. In addition, the wall deals 5d6 fire damage to any creature passing through it. The wall deals double damage to undead creatures.
If you evoke the wall so that it appears where creatures are, each creature takes damage as if passing through the wall. If any 5-foot length of wall takes 20 or more cold damage in 1 round, that length goes away.