Viper is a wooden roller coaster located at Six Flags Great America in Gurnee, Illinois, which opened in 1995. Viper is a clone of the Coney Island Cyclone and is the only roller coaster ever to be built directly by Six Flags. Viper is also the only wooden roller coaster with this name (all other roller coasters named Viper, both operating and not, have been steel roller coasters). It was built by Rygiel Construction.