This breathtaking (ba-dum tss) monster is the choker, also known as the reason why you don't walk single file in dungeons.
For a small creature, chokers are a surprisingly adept grapplers. A +4 racial bonus to grapple checks and a +6 bonus to strength make them better grapplers than halflings, humans, and even orcs. On top of that they constrict their victim's throat, preventing both speech and verbal spellcasting. This means that your grabs restrict verbal, somatic, and most material components.
Another fun quality of chokers: they have reach, meaning a creature that approaches you may get attacked, grabbed, and held in place before it can even attack you. On your turn you can then let go, retreat a bit and repeat.
And then there's Quickness, probably one of the most broken abilities in the entire game. It gives you an extra standard or move action on your turn, every turn. Add an extra strike to your full attack? Solve melee problem #1? Perhaps cast two spells a turn at no penalty? Quickness is a very, very good thing to have.
Finally, chokers get a few abilities that ought to be mentioned. Improved Initiative as a bonus feat, a slow climb speed, and darkvision. Neat, but not necessary.
To be honest, I'm not sure a creature with Quickness should have 9th-level spells or maneuvers. This would put the choker's LA at +2, which sounds about right to me. A choker in itself may be a little underpowered at that LA, but the potential reward at higher levels is so great that anything below +2 would make chokers a no-brainer, which I want to avoid.