Ferret said:
What if you are drained 10 strength points as bear, when you shift back what happens if you have less then 10 in str? Do you collapse as usual or something special
You'd collapse, I'm pretty sure. Why would anything else happen?
There's an interesting follow-up question, however. Imagine that you have a str of 8. You shift into bear form, and you get a str of 19 or so. You take 10 points of damage, and then you shift back into your normal form.
So far, so good: your STR is now 0, since there's no such thing as a negative ability score.
But what happens when you change back into a bear?
1) When you shifted back into a human, you still had 10 points of temporary str damage; however, 2 of those points didn't apply for as long as you had a str of 8. When you shift back into a bear, all 10 points apply again.
2) When you shifted back into a human, you only had 8 points of temporary str damage, since it's impossible to have more points of ability damage than your ability score. When you shift back into a bear, you only have 8 points apply.
I'm strongly in favor of #1, even though the rules don't explain it well. Otherwise, druids who take any str or dex damage would be well-advised to shift into a form with a low score in that area, and then shift back into their normal form; shifting into the low-stat form, under scenario #2, would essentially heal a bunch of points of temp ability damage.
Daniel