Final answer:
The metal instrument shown in the photo by Anton Petrunin is called a mouth harp. It is a chordophone that is played by vibrating a metal or bamboo reed against the player's teeth or lips.
Step-by-step explanation:
The metal instrument shown in the photo by Anton Petrunin is called a mouth harp. The mouth harp, also known as a Jew's harp or jaw harp, is a musical instrument that is played by vibrating a metal or bamboo reed against the player's teeth or lips. It is classified as a chordophone, which is a type of instrument that produces sound by vibrating strings.