In Monster Hunter World you can talk to a researcher on the map “Coral Highlands” and she will issue a bounty called Research Help: Wiggler Capture.
This is a short bounty that requires you to catch 3 Wigglers in Coral Highlands. Those are the small worms sticking out the ground, they can be found near the southern camp. They will retract into the ground when you get close, even if you are sneaky.
But there is a very easy trick to capture the Wigglers:
Simply put on the Ghillie Mantle (at camp go in the tent, change equipment and instead of health booster pick the Ghillie Mantle). Then the Wigglers cannot see you coming! The same trick works for all other monsters/animals in the game. Now run up to the wigglers (they can’t hear you either) and use the capture net (automatically in your inventory at all times) to capture one of them. Below is a screenshot of what they look like and their location (in green circle).
The other wigglers will retract into the ground but worry not! Simply fast travel back to the southern camp and by the time you get back to them they will have come out of the ground again. You can also wait nearby or just run around the map, although fast-traveling back to camp is the safest bet. Finish the bounty by talking to the NPC at the research center in Astera and all is done.