That's how all bonuses work? If I'm reading your comment correctly. If you leave a company within, usually, two years, you have to return the money.
I totally agree, I don't really like it. I think, though, that the astronomically large bonuses are worse than the small ones. Paying back $5000 (+ income tax, mind you) is much easier than paying back $100k + tax.
As for signing bonuses, I have read contracts from various startups that want you to pay your signing bonus (which is generally about 5k) back if you leave within the first year.
I have heard stories from other employees, claiming that entire teams were fired, and workloads were transferred to the remaining employees - however they have been just that - unverified rumors.