Thanee said:
And why is a tattoo not an object? What else should it be? It's physically present, after all.
You do not conjure the ink of the Tattoo, it is supplied as a 100 GP material component.
You draw the tattoo on (effectively since you need artistic Craft skill). It has a 10 minute casting time.
It is listed as a Conjuration (Creation) spell, but it doesn't create any Conjuration effects, mostly Abjuration effects.
The author got it totally wrong. It happens.
Examples of core spells that Create Magic Tattoo comes close to mimicking:
+2 Resistance Bonus to one type of save (Resistance, Abjuration)
+1 Luck Bonus on attack rolls (Divine Favor, Evocation)
+1 Deflection Bonus to AC (Shield of Faith, Abjuration)
+2 Resistance Bonus on all saves (Resistance, Abjuration)
+2 Competence Bonus on attack rolls (Guidance, Divination, no other core spell gives a competence bonus on attack rolls)
Spell Resistance (10+1/6 caster level, super wimpy), (Spell Resistance, Abjuration)
+2 Enhancement Bonus to ANY one ability score (Bull's Strength, Transmutation)
+1 spellcasting ability - I cannot find a core spell that adds to spellcasting ability, this is borderline broken, even the Ring of Arcane Might requires Limited Wish (Universal) and Greater Magic Weapon (Transmutation) to craft.
Maybe the Universal school would be a good one for this spell since it touches on so many different schools of magic.
Quite frankly, I want some of what the designer of this spell was smoking. He combined all of the Enhancement bonus spells into one spell (granted, +2 instead of +4, but for 24 hours instead of 1 minute per level). He rolled a bunch of Abjuration spells into a Conjuration spell. And he created a spell with 9 separate distinct effects.
Not only that, but Shadow Conjuration also has another problem with respect to Create Magic Tattoo. It does not require Material Component costs like all other spells which mimic other spells. That's a game design flaw (with Shadow Conjuration, not with Create Magic Tattoo). Course, few of the core Conjuration(Creation) spells have an expensive material component except Mordenkainen's Magnificent Mansion (15 GP at 7th level) and Wall of Iron (50 GP at 6th level) and Sepia Snake Sigil (500 GP at 3rd level). Most do not have a material component at all.
Course, of these 3 (and all of the other core Conjuration (Creation) spells), all of them have an easily discernable visible effect. The Tattoo can be easily hidden so nobody even knows it is there (so, the DM might not require a Will Save for interacting with something you do not directly interact with or see).
I'm not impressed with the game knowledge of the designer of this spell. This is how balance problems creep into a game because a game designer doesn't know what he is doing.