Viper
From Memory Alpha, the free Star Trek reference.
A viper is a type of snake.
Three vipers were mentioned by Trakor in his third prophecy. When the prophecy began to come true in 2371, many believed that three Cardassian scientists were the "vipers" who would destroy the Celestial Temple, although it was later revealed that the prophecy was referring to three comet fragments. (DS9: "Destiny")
