These are two of Kakuzu’s five hearts, held together by many black threads. Kakuzu is a member of the Ataksuki clan.
This is an ink painting, and is available for purchase. I thought it would be cool to do something like this because then ‘grown-up’ anime fans could display anime fan art as regular artwork in their home and not come off like “some weirdo who still likes cartoons”.
Naruto (c) Masashi Kishimoto