We meet most Mantis Shrimp when we’re diving over the sand at Mae Haad and Chaloklum Bay on Koh Phangan. They quickly withdraw into their hole if alarmed, so are not easy to photograph on SCUBA dives. We first saw one out and about in 2016. Its banded body suggested that it must be a “spearing” mantis shrimp; Lysiosquilla maculata.
In 2015 we saw our first “smashing” mantis (note the cylindrical rather than flat eyes), which we think is Odontodactylus japonicus. Their fascinating hunting techniques (and more) are explained in Wikipedia