Spells are Ooze type monsters which have been brought into being by a caster.
The most common Living Spell found is the Living Meteor Swarm. For the purpose of Bane weapons and creature types a living spell is considered to be an Ooze type. A Living Spell can generally cast an unlimited number of the spell it was created from, and one additional, often similar spell as its normal attack. For instance a Living Meteor Swarm will be able to cast the Arcane spell Meteor Swarm and the Divine spell Cometfall an unlimited number of times until it is destroyed.
Living Spells can be as varied as the spells they are created from.