Spell that adds SA dice?

[Zombimode]

I recall there being a spell that adds Sneak Attack damage dice for one attack (or one round). Somewhere in the Spell Compendium.
But now I just can't find it.
Does someone knows the name?
Or am I misremembering things?

[Flickerdart]

Hunter's Eye, PHBII.

[mabriss lethe]

There was also a 1st level assassin/bard/sorc/wiz spell in SpC: Critical strike. Swift action, 1 rd duration grants 1d6 damage in a manner identical to sneak attack (though never calling it such.) it also doubles threat range and gives you +4 to confirm a crit.

[The Viscount]

For the sake of completeness and it case it was what you were talking about:

Vital Strike is an Assassin 3 spell that lets you add your sneak attack damage without fulfilling normal criteria (it counts as a normal SA so you can use staggering strike etc.)

Wracking Touch is a Druid 2 Sor/Wiz 2 spell that deals 1d6+1 per cl (max 10) that also lets you pile on any SA dice you may have without fulfilling normal criteria.