Some of these pictures and descriptions may give away plot details that you might not want to know before watching the film.
This was made by experimental and controversial French filmmaker Gaspar Noe, whose films tend to be shocking, extremely violent, uncomfortable to watch, and visually amazing. The camera seems to go anywhere and everywhere, passing though walls and flying through the air.
It's set in a Tokyo full of glowing neon lights and dark nightclubs. We see a young American drug dealer betrayed by a friend and shot to death by the police in a squalid bathroom, then we see the rest of the film from his perspective as he or his soul floats out of his corpse and around the city to a soundtrack of electronic and pop music. Sometimes we see things from his perspective in what seem to be past memories.
In one of these flashbacks, we see him in the apartment of a drug dealer who talks to a snake in a terrarium and asks if he likes snakes. They finish their drug deal then we fly somewhere else. Even in psychedelic foreign art movies, drug dealers are the sort of anti-social sickos who can be identified as such not only from their profession, but because they keep snakes as pets.