People heard him before they saw him, mumbling â€” croaking, really â€” in a low voice that seemed to come from nowhere. â€œIs the show starting?â€ Then: â€œHold up, hold up.â€ Then, seemingly to an assistant: â€œI donâ€™t want to fall.â€ This was good news. It was Tuesday at the B. B. King Blues Club & Grill, and Sly Stone was in the building.