When I noticed several of these “fancy” snails slinking along the sidewalk where we dined one evening, I asked the waitress why the shells were so fancy. She told me she’d never really noticed them before I pointed them out. While they were not the very rare Pūpū kani oe, or tree snails endemic to only the Hawaiian Island of Oahu, they still were very interesting to watch. They were everywhere at dusk!
Real Mom Time (RMT) 
That would be a giant African land snail, considered one of the most damaging invasive snails in the world
Thank you for writing so long after I’d posted this photo! I knew it wasn’t the other snail, and while my caption mentioned that fact, the title of my image conflicts. I will edit accordingly. Thanks again!