Fins to feet

(Spell Compendium, page 92, DnD 3.5)

Transmutation

Level: ; Druid 2; Sorcerer/Wizard 2
Components: V, S
Casting Time: 1 standard action
Range: Touch
Target: Willing creature touched
Duration: 1 hour/level
Saving Throw: Fortitude negates (harmless)
Spell Resistance: Yes (harmless)

The naga's lower extremities thrash about and slowly transform into humanoid limbs.

This spell transform tails, tentacles, or finned extremities into humanoid legs and feet. Creatures so affected lose any natural swim speed they possess, but gain a land speed instead. Transmuted Medium creatures have a base land speed of 30 feet, Small and smaller creatures have a base land speed of 20 feet, and Large or larger creatures have a base land speed of 40 feet.

The subject loses any natural attacks based on its tail or tentacles.