I would say first things first, soak the shit out of it with WD40, PBBlaster, Silicone Spray, whatever you have.

If you cant loosen it with a ratchet, slide a pipe over the end of the ratchet for more leverage. If its stripped, itll just spin. If its stuck, you have to be able to get it out. Worse comes to worse you get the ratchet, extension, a long pipe and a hammer...itll come out.