I'm just going to quote from the YouTube description of this video.
Native snails in NZ are big, mean and carnivorous. They hunt their prey by stealth. When the attack comes, it is sudden, ruthless and fatal.
This is the best thing I've heard since the guy from the Smithsonian National Zoo told me about the time he was bitten by a sloth, a story which included the words, "It all happened so fast."