Transdimensional Spell (Metamagic)

You can cast spells that affect targets lurking in coexistent planes and extradimensional spaces whose entrances fall within the spell’s area.

(Complete Arcane, p. 84)  
Originally posted on D&D tools

• Prerequisite –
• Benefit – A transdimensional spell has its full normal effect on incorporeal creatures, creatures on the Ethereal Plane or the Plane of Shadow, and creatures within an extradimensional space in the spell’s area. Such creatures include ethereal creatures, creatures that are blinking or shadow walking, manifested ghosts, and creatures within the extradimensional space of a rope trick, portable hole, or familiar pocket. You must be able to perceive a creature to target it with a transdimensional spell, but you do not need to perceive a creature to catch it in the area of a burst, cone, emanation, or spread. A transdimensional spell uses up a spell slot one level higher than the spell’s actual level.
• Normal – Only force spells and effects can affect ethereal creatures, and no Material Plane attack affects creatures on the Plane of Shadow or in an enclosed extradimensional space. There is a 50% chance that any spell other than a force effect fails against an incorporeal creature.