For sale is a copy of Batman & The Joker: The Deadly Duo #6 Bill Sienkiewicz Batman Variant cover, which signed in white ink by cover artist Bill Sienkiewicz at the 2025 San Diego Comic-Con and by writer Marc Silvestri at the 2025 TerrifiCon. It was witnessed by CGC and graded CGC Signature Series 9.8. The book has white pages and a custom Batman CGC label. It is a great-looking cover. According to a recent CGC population report, there are eight copies of this book graded CGC Signature Series, and this is one of four copies graded 9.8, with none graded higher.