Grizzly II is the sequel to the 1976 Jaws ripoff Grizzly. Technically, there is two movies known as Grizzly II: Claws, a rare, VHS only film which was re-titled in Mexico and Canada, and Grizzly II: The Predator, aka Predator: The Concert, or a variety of other work-in-process names.
Filmed in 1983, the movie never saw a proper release. There is a multitude of stories as to why, the most common involving the producer running off with the budget, or the bills for the equipment not being payed, resulting in the Hungarian government seizing most of the productions materials. In 1987, Cannon films picked up the movie with intent on releasing it, but started having financial issues in 1988 and forgot the movie. Its existence was often doubted until 2007, when it finally surfaced, albeit unfinished.
Grizzly II is a fairly basic killer animal movie, like its predecessor. The basic story involves a massive concert being held at a national park, at the same time that a massive, prehistoric grizzly bear awakes and starts attacking people in the park. A native American tracker is called in (he often refers to the bear as an evil spirit, ripping off Claws) but is unable to prevent the bear from attacking the concert, which is eventually killed.
What was finished
The unedited version of the movie is very rough. Most of it is rough filler, using tons of concert footage (preformed by Nazareth), most of the bear footage wasn't filmed due to the special effect not being quite finished, and the quality of the film is very poor. The soundtrack is a mess, although a few songs made for the movie are still intact. There are continuity errors near the end, the shadow of the camera man can be seen in a few scenes, and all but a few scenes near the end of the film that involved the bear are blank film with roaring noises played over it.
There is a fan edit that adds footage from movies like Grizzly, Claws, and Day of the Animals over the blank film, although it has yet to surface on Youtube.
Although the animatronic bear was never footage, there was a puppet used in a few scenes. In an old upload of the movie, there was a comment made by someone who worked on the movie who stated that it had been altered, and didn't use the puppet they had made. It is possible there was more special effects footage made and unused, but as the movie is relatively obscure, it isn't known for sure. As the old 10 part, low-quality edit was removed from Youtube, the statement was lost.
The other Grizzly II
For the sake of discussion, Claws is equally obscure and hard to find as the real version of Grizzly II. It's a cheaper looking movie than Grizzly, due to the lower quality film and lack of restoration, and has never seen a higher release than VHS. Released in 1977, this direct knock-off of Grizzly is a much hated film, although more creative when compared to Jaws. After being wounded by hunters, an Alaskan Grizzly bear (which would be larger than a grizzly from Yellowstone park bears) goes on a killing spree. Eventually, with the help of a native American tracker, the bear is hunted down and killed in a flaming bear vs. ax fight.
There is very little known about the making of the movie, and if it will ever see a proper release on DVD or Blu-ray. It seems to be public domain, unlike Grizzly II, and is still mistaken as the sequel to the more successful film.
The IMDB article, which has some information
The IMDB article on Claws, which highlights what little is known about it