After reading the spell, I'm quite confounded about the thinking behind Mass Charm Monster. It's the only Mass spell that affects 2x caster level in hitdice, making it pointless over it's (much) lower level single target version. You will usually get one, maybe two, targets out of this 8th level spell. Mass Hold Monster is only one level higher at 9th, a much more powerful effect, yet has UNLIMITED targets in the area.
Why deviate from 1target/lvl that all the other Mass spells ascribe to? Seems gratuitous to carve out a niche for Mass CM when the effect isn't that outrageous.
BTW, the spell description promises to affect at least 1 creature. Really.
