Euglandina rosea , Photo: Tim Ross
Euglandina rosea, common names the "rosy wolfsnail" or the "cannibal snail", is a species of medium-sized to large predatory air-breathing land snail, a carnivorous terrestrial pulmonate gastropod mollusk in the family Oleacinidae.
This species is native to tropical North America. It has become an invasive species in many other places, including Hawaii.
These predatory snails were originally introduced to Hawaii in an attempt to eliminate another invasive species, the giant African land snail. However, the introduced species also vigorously attacked the indigenous O`ahu tree snails. As a result many tree snail species were hunted to extinction within the first year. These predatory snails continue to represent a threat to the local snail fauna.
The rosy wolfsnail has a light brown elongated shell and a light grey, or brown body. Its lower tentacles are long and almost touch the ground. The shell is often 40 to 50 mm in maximum dimension but can sometimes be as large as 60 or even 70 mm. 
This species is a fast and voracious predator, hunting and eating other snails and slugs. The smaller species of prey are ingested whole. This gave it the nickname "the cannibal snail".
Source: Wikispecies, Wikipedia: All text is available under the terms of the GNU Free Documentation License