"Hey Bob, we need one more fire-based monster for the next book."
"How about we take a spider, give it a goblin head, and make it fly and suck blood?"
"How is that related to fire?"
"We'll just say it is."
Rast are low-level outsiders with four HD and the fire subtype. Their land speed is abominable, but they are pretty good fliers. Ability scores are reasonable (net total of +4) but intelligence will almost always be terrible.
Improved Grab and Blood Drain are already nothing special, but a rast's inability to bite and claw in the same round (why, WotC, why?) makes it even worse. At least a mouthpick weapon isn't out of the question: many rogues will value four additional attacks each round.
Last is paralyzing gaze, which does exactly what you'd expect. Its non-friendliness hurts, though, and Narrowed Gaze isn't exactly easy to get as something barely smarter than a camel.
I think +0 LA is fine: debate away.
The very interesting (but also underused) ravid are next.