Twilight knife a must have?

Is twilight knife (APG) a must have spell when taking Spell Blending?

You can cast it immediately prior to your full attack AND it essentially doubles your number of attacks for the next X rounds (and unlike your attacks, its attack bonus doesn't go down with the iteratives). If you have a haste effect on yourself, your DPR can get pretty sick real fast.

Also, would the twilight knife benefit from such things as arcane accuracy?

EDIT: It just occurred to me that, for the purposes of twilight knife's attacks, some people interpret casting a spell at your enemy to be an attack. That means that in succeeding rounds, twilight knife will get an extra attack if you use Spell Combat to cast a spell at the enemy in addition to your full attack.

Stack in Critical Strike (a dagger is a melee weapon) and your odds of getting a crit as well as the opportunity to cast yet another spell goes up dramatically!

Umm...fairly certain you only get one attack with twilight knife as the wording for the spell says attack...as in singular...for what the spell does in the round it's active.

I think that you are wildly over-estimating this spell. By my reading, it attacks once per round. It uses your BAB +Int, and gets no other bonuses to its attack.

It does not benefit from any abilities you have, like Arcane Accuracy. It gets one attack at your BAB +Int. No enhancement modifiers, no Str to damage, no Haste, none of that. The most it can do is 1d4+5d6 once per round if it has flanking at 20th CL.

It doesn't use your feats, and it's not counted as YOU for the purposes of triggering things like Arcana.

Umm...fairly certain you only get one attack with twilight knife as the wording for the spell says attack...as in singular...for what the spell does in the round it's active.

That can't be right. I suspect you two are misreading it.

After all, I had a hard enough time trying to find reason to use it under my interpretation (since you cast it as a standard action, you always waste the first round).

It's like, the worst 3rd-level combat spell ever if you're right (which I don't believe you are).

We're right. And it is bad. Not trying to be a jerk, but it's just a bad spell, unless you are playing some sneak-attack caster that needs to create his own flank (and even then you're probably better off casting Summon Monster).

As for the reasons why they are right:

the knife has your BAB, but you need to make a full attack to gain those 2 attacks (still ridiculous). The knife however only "attacks", which is confirmed by it's movement to flank.

For a controller it's a bit of extra damage, might even help a rogue, but it's still more of a second lvl spell.

2nd is even still kinda weak...honestly for a wizard, this should be a 1st level spell.

I think it only makes one attack per round. I suppose it's possible that it gets iteratives if you do, though. I kind of doubt it.

Sometimes there are crap spells. It seems like this is one of them.

Reading the spell description, especially the part "The knife uses your base attack bonus ... when making this attack" tells me that it only makes one attack per round.

I would still not call the spell useless, however, since it inflicts force damage (which means no DR and also damages incorporeal creatures), and the spell only states that you must attack the creature in order to make the knife attack - it does not state that you have to attack it with melee, ranged attacks and spells will do also. Also, you can order the knife to flank your opponent with someone else - so you can order it to flank the opponent with the party rogue, making both the knife and the rogue deadly.

I guess that this is a spell that can only be used effectively in certain situations, which makes it a perfect spell for a spontaneous caster, like a sorcerer, but not for a magus, who must prepare his spells ahead.