Some of these pictures and descriptions may give away plot details that you might not want to know before watching the film.
There is no snake in this movie, but there is a cool snake-venom murder weapon that I thought was worth a mention.
This is a thriller starring Blake Lively who plays Stephanie Patrick, a top Oxford student who became a junky prostitute after her family was killed when terrorists bombed a passenger plane. A journalist who is trying to expose the terrorist organization contacts Stephanie, but the terrorists find out and strike back. She leaves London for the countryside where after some jogging and training she becomes a highly-skilled assassin, but not the glamourous kind we usually see in movies. (It's amazing that the movies think you need lots of skill and training to kill people. The daily news headlines prove otherwise.)
Stephanie sets out to assassinate the terrorists who were responsible for the bombing. She travels to Tangiers to kill one of them at his home, where we see a large lizard just sitting loose on his kitchen floor. (Is it a pet? Do giant lizards roam the streets of Tangiers like stray cats?) She sneaks into a dark room to kill the bad guy, but there's a struggle. He pulls out a giant syringe and tries to inject something into her with it, but he fails and she kills him. She takes the syringe with her. It's labelled Taipoxin. She Googles the word and finds that it's engineered purified venom from the Taipan, an Australian snake, that results in immediate death on contact. (It's a fact that the Inland Taipan produces one of the most deadly snake venoms on the planet, but I wonder if it would really kill so quickly.) Stephanie saves the syringe to use later on her number one target. When she finally stabs him with it, he does die immediately, as advertised.
I figured if a junky/prostitute/assassin can Google Taipoxin, I can too. I learned that it's a real thing. It's described as the most lethal neurotoxin isolated from any snake venom to date. You can buy it freeze-dried online for a few hundred bucks, but it doesn't seem to be sold in a clearly-labelled giant syringe for use by terrorists and assassins. I'll bet it doesn't take very much Taipoxin to kill someone, so there's no reason the syringe would be so enormous. It probably needed to be big enough in the movie that we could read the label, and a giant syringe certainly makes a much better movie weapon.