Some of these pictures and descriptions may give away plot details that you might not want to know before watching the film.
A cobra fights a mongoose in a gambling pit in Madagascar while Bond and his assistant watch one of the gamblers, a mercenary bombmaker. The bad guy realizes he's being watched so he jumps into the arena to get away from them, almost stepping on the cobra before he runs out of the arena beginning the usual long chase scene that starts a Bond movie.
I don't know if the commotion spoiled the contest or if they continued the fight after the big chase scene, but we never find out the outcome. My money was on the mongoose.
I thought that the cobra was all CGI, since the fangs look so fake, but there's a page on reptilerentals.com that shows someone filming a Banded Cobra. It probably is CGI that was based on the film of the rented snake.