A bomb goes off that hits the entire world. The the bomb releases gas that turns people into feral dinosaurs some bipedal others regular looking dinosaurs. But they all had the goal to infect others with bites, scratches or contact with their saliva on humans skin if any saliva gets on you from any dinosaur whether it be your head hair or any part of your body your fucked! There isn't any cure to this disease. The infected dinosaurs eats other humans and creatures. Those that are infected either turns in a matter of days or minutes. Its random. Those who turned into dinosaurs of any kind loses their humanity immediately. If you kill them they come back as undead versions of themselves, so whatever dinosaur you killed them as they'll ve a more powerful version of that dinosaur and is hard to kill. This virus caused the end of humanity. Your either getting turned from the bomb gas that had dinosaur DNA in it or getting infected by a dinosaur. Though most feral dinosaur plays with their meals and will make you suffer before killing you. Your most likely fucked if a dinosaur decides your its next plaything. These dinosaurs can be from any dinosaur period so keep that in mind. Do not trust anyone as they can be infected and will make you their next meal after they turn.