How to fight grounded fireflies?

The game is like this: you can lead it to the flower with a hole in the middle of the ground, and the fireflies will run over and swallow it themselves, and then you can get a material. There is a heritage box in the initial town, which is the main line leading to the forest. After joining the guild, grandma will give you the key to the town, and you can open the door of the town storage room, which contains an inheritance box.