Rice field crabs: Pu na (ปูนา). When pickled they are most often called pu dong (pickled crab; Thai: ปูดอง), or less often pu khem (salted crab; Thai: ปูเค็ม), and frequently used in papaya salad or as the main ingredient in yam pu dong (yam-style salad made with pickled crab).
The people, the food, the language, Thailand is an amazing country, learn about its interesting history.