How bad is it? It's one of the better SyFy originals.
Should you see it? Yes, though it's pretty mediocre.
This is not the (better) 2009 film of the same title, but a SyFy (at the time Sci Fi) network film with a better than average cast, including Summer Glau and Tom Skerritt. A spaceship crashes into a Louisiana museum and reanimates a frozen woolly mammoth stored there. The government plans to stop it by blowing up the entire area with a nuclear bomb, so there's a 17 hour limit in tracking down the beast (not hard, as it's pretty big) and killing it. Molten steel doesn't work, but they get the idea of refreezing it with liquid nitrogen and it ends up being put back on display. The CGI is no great shakes, but the film accomplishes the little it sets out to do.