Transmute Rock to Magma

Suggested spell level?

Transmute Rock to Magma
Transmutation
Level: Drd ?, Sor/Wiz ?
Components: V, S, M/DF
Casting Time: 1 action
Range: Medium (100 ft. + 10 ft./level)
Area: Up to one 10-ft. cube/level (S)
Duration: 1 round/level (D)
Saving Throw: See text
Spell Resistance: No

This spell turns natural, uncut or unworked rock of any sort into an equal volume of dangerously hot magma. Magical or enchanted stone is not affected by the spell. The depth of the magma created cannot exceed 10 feet. Creatures unable to levitate, fly, or otherwise free themselves from the magma sink until hip- or chest-deep, reducing their speed to 5 feet and giving them -2 penalties on attack rolls and AC. A creature caught in the magma suffers 6d6 points of fire damage per round of exposure. Damage from the magma continues for 1d3 rounds after exposure ceases, but the creature suffers 3d6 points of fire damage per round.

If transmute rock to magma is cast upon the ceiling of a cavern or tunnel, the magma falls to the floor and spreads out in a pool at a depth of 5 feet. The falling mud and the ensuing cave-in deal 4d6 points of crushing damage and 6d6 points of fire damage to anyone caught beneath the area, or half damage to those who succeed at Reflex saves.

Once the spell's duration expires, the magma reverts to rock.

Arcane Material Component: A bit of igneous rock.

First thought 8th for SOR/WIZ, 7th for druids.

Neat spell.

I believe there's a 6th-level (?) version in one of the early 3e Dragon mags, if it helps- though I'm not sure exactly which issue it was in.

Include rules as to what happens if a character falls into the magma, is submerges and survives, just as soon as the spell ends and the magma turns back to rock. Sad way to lose a char.

just a suggestion--I'd increase damage to 8d6 in / 4d6 after you're out, and allow a Fortitude save for half damage.

I dont know which edition you're going for since I came here via link but the 3.5 Spell Compendium has this exact spell (lava instead of magma but it's the same thing) on p. 222 listed as a 9th level spell if that helps

I prefer the direct approach. Transmute Target to XP!