This is not common at all. What is common is to have such a clause apply to the period of employment but not after.
Please feel comfortable telling your employer to remove it (many people don't know that every contract is negotiable).
Please feel comfortable telling your employer to remove it (many people don't know that every contract is negotiable).
It doesn't necessarily mean that they plan to screw you. But it certainly means they don't trust you, and it brings all the downsides of lack of trust.
It also means that they're effectively filtering out talent, so your colleagues are unlikely to be very good.
If you have any other option I would take the other option. If you have no other options I would redline it and send it back. But whatever you do do not sign that clause.
One could mess with the employer: offer an amendment where they own your work forever, but they pay you, forever, for your time, at whatever rate you set. :)