How to get the crystal cancer card of Viper Knight prequel?

1. In "Prequel to the Great Knight", players can find crystal cancer in the crystal mine. Br>2. Crystal Cancer will be in the Crystal Mine all day, and players can go to the challenge at any time. Crystal cancer is the crystal mine in the fourth picture, and it is the Boss of attack and defense. Will attack enemies near the body with pliers; Will send out a long laser, scattering many blue magic bullets around; Summon two rings in front of you, and then scatter them in the form of magic bullets; Hit the ground downward for a crystal stab attack; There are also defensive skills, damage absorption.