Force Missile Mage.
You enter the PrC, you feel awesome and cool, the picture reminds you of a inquisitor-esqe character that feels kick-ass.
When you leave it, you realized you took 5 levels in a PrC which only benefit was improving a lvl 1 spell.
Oh, and gaining a free Quickened Shield.
....
Now, if I could just find some class feature/metamagic/other that'll turn Magic Missile into a de-buff spell then I'd be happy.
Daze, nauseated, immobilized, slowed or something. Just auto-hitting with minor force damage isn't all that hot, unless your campaign is about eradicating etheral creatures.
First I thought about Fell Drain, but no sane DM would let it stack on a single target, regardless of if it's RAW or not.