Russell’s viper, Daboia russellii
Vipers kill their prey using hemotoxic venom, which essentially turns their victim’s blood into plastic. Solidified blood causes pain, massive swelling, paralysis, and necrosis in extremities, and when hemotoxic envenomation reaches the vital organs, death typically ensues.
This is what happens when a single drop of venom from a Russell’s viper (the deadliest Asiatic viper) is dropped into a petri dish of blood.
Hat tip to Karen L. Myers.