Pre-90's (?) Sinbad-like fantasy movie with an invisible monster in a Roman-like arena

Question

I'm looking for an old fantasy movie, but I need help because I don't know the title, cast names or year of release.

Here's what I remember:

• I thought it was one of the Sinbad movies, but I already looked at the trailers and I don't recognize any of them as the movie I'm looking for, so it could be a non-Sinbad movie.
• I remember a funny line from the villain. When he plans some wicked doings in the beginning of the movie, one of his assistants (or similar) tells him something like "But sire, the people won't like it" to which he replies "the people, that scum!" with an angry look on his face.
• There's an extended scene in a foggy jungle that has a number of perils, like crocodiles and carnivorous plants. Some of the hero's buddies get snatched by these foes.
• The movie is entertaining but the special effects are very cheesy. For example, the crocodiles in the jungle are obviously stuffed animals or something, as they don't move and just 'slide' over the terrain and water.
• I think there's a battle near the end between the hero and an invisible monster in a big Roman-like arena.
• The movie is very probably from before 1990, either 80's, 70's or even earlier.
• I think there's a goofy wizard somewhere in the movie, with lots of colored smoky potions going on around him.
• The hero has dark hair (not 100% sure about this detail).

Can someone help?

Answer 1

This is Captain Sindbad (1963).

To marry Princess Jana, Captain Sindbad must battle deadly obstacles and fight El Kerim, the evil ruler who also wants to marry the princess.

Near the start of the film, Captain Sindbad and his crew are sailing home to the kingdom of Baristan, where he plans to marry Princess Jana. Unbeknownst to him, the kingdom is now ruled by the evil El Kerim, who usurped the King using the power of a magic ring stolen from the King's magician, Galgo the Great (a character played for laughs), and is intent on marrying Princess Jana himself.

Around 50 minutes into the film, Sindbad is captured and forced to confront an invisible monster in a large arena packed with spectators.

Around 59 minutes into the film, the following dialogue is exchanged between El Kerim and his second-in-command, Col. Kabar.

EL KERIM: Those are my final orders. Sindbad must not live another day. No capture. I want him dead.

COL. KABAR: Your orders will be obeyed, sire. A hundred detachments are already scouring every hiding place in the kingdom. Sindbad is finished.

EL KERIM: Then there is no further need to delay the wedding.

COL. KABAR: But the King's consent! The people will not like it if their Princess is forced to marry against her will.

EL KERIM: The people... those scum!

_{Captain Sindbad (1963)}

In the following scene, Sindbad and his crew begin a trek through a foggy swamp, during which one of his men is pulled upward by vines, never to be seen again, whilst another wanders off on his own, only to be surrounded and eaten by crocodiles.

The crocodiles are rubbery-looking and slide along the ground as you described. The special effects in general are quite poor, even for the time, and unlike the Sinbad films produced by Ray Harryhausen, there's no stop motion animation.

You can watch the whole film at the Internet Archive, but here's a trailer.