A banishment spell is a more powerful version of the dismissal
spell. It enables the character to force extraplanar creatures
out of the character's home plane. Up to 2 HD of creatures per
caster level can be banished. To target a creature, the character
must present at least one object or substance that it hates,
fears, or otherwise opposes. For each such object or substance,
the character gains +1 on the character's caster level check to
overcome the target's SR (if any) and +2 on the saving throw DC.
At the DM's option, certain rare items might work twice as
well (each providing +2 against SR and +4 on the spell's DC).