Sumatran Pit-viper

The Sumatran pit viper, also called the Sumatran tree viper, is a large, heavy-bodied venomous pitviper with a prehensile tail, now often placed in the genus Parias. It is found in the tropical forests of Indonesia, Malaysia and Thailand. It is arboreal and pale to neon green with a red-tipped tail, and adults may attain 1.6 m snout–vent length, with fangs over 10 mm long (Wikipedia, general species account).