The Kumi Lizard is a cryptid reptile, possibly a giant monitor lizard, which allegedly once lived in New Zealand. It is similar to the giant extinct Australian lizard Megalania except that it allegedly lives in trees.
In New Zealand Mysteries, author Robyn Gosset refers to a sighting of a Kumi in 1898 by a Maori bushman. Its length was estimated at 1.5 metres. In the first edition of the book, Gosset refers to several more accounts of the lizard which are absent from the second edition. These include an account from captain James Cook, who was told by Maori in Queen Charlotte Sound that huge, arboreal lizards were present in the surrounding bushland, and that they were greatly feared, as well as a sighting from 1875 of a large lizard washed up in a flooded Hokianga river and the discovery of bones possibly from the animal that same year. In more recent times sightings have become rarer. The most recent reports both come from 1898, one describing a large reptile seen near Gisbourne, the other a huge creature akin to a monitor lizard which threatened a bushman in Arowhana before retreating into a Rata tree. Although the animal itself was not spotted again, photographs of its footprints were taken.
One possible explanation could be the crocodile monitor, Varanus salvador, which is native to New Guinea. Crocodile monitors can grow to 13 feet in length, and, throughout their lives, spend at least part of their time in the trees. Since monitors are good swimmers, and crocodile monitors do live on an island, it is not impossible that the crocodile monitor is the source of the legend.