Some of these pictures and descriptions may give away plot details that you might not want to know before watching the film.
This is a sequel to Jumanji: Welcome to the Jungle (2017) which also had some snakes. The same cast is back, but this time some of them inhabit different characters, and there are some new players and some new game characters to keep things interesting.
In the beginning, just after they entered the world of the Jumanji video game, the experienced players are describing the game to the confused newcomers. After a hippo nearly kills Kevin Hart's character, Jack Black's character is warning the new players about the dangers that can kill them. He is pretentiously explaining how he is always aware of his surroundings, when a gigantic snake above him that he was not aware of swallows his head and drags him up into the trees. The others stand with shocked expressions. Then Black falls from the sky, unintentionally illustrating that players in the game can die and come back to life, but only three times. It's a comic scene, but it also provides some necessary exposition for the audience who may not have seen the previous movie. The giant CGI snake looks a lot like an Anaconda, and it might be a nod to the 1997 movie franchise.
There is a second snake scene. Unlike the first scene, these snakes are stationary and not supposed to be alive, but since all the snakes in the movie are computer-generated effects, it hardly makes any difference to me. Near the end of the film, the group has entered the fortress of their enemy, Jurgen the Brutal. One of them has become a character that is a flying black horse, and he was captured and put in a cage in a very large building. Seaplane (Nick Jonas) sneaks in to rescue the horse, but he finds that the building is lined with snakes (carved out of stone or something similar) that shoot deadly darts. He is shot and killed by a dart, dissappearing into a cloud of dust, then he falls from the sky and returns to the game to try again. He dies twice from the snake darts before he learns that stepping on certain stones triggers the darts. He learns to avoid the stones and the darts, and rescues the horse.