The Flash 6×16 “So Long and Goodnight” Season 6 Episode 16 Promo – BLACK HOLE THREATENS JOE’S LIFE – After Black Hole hires Rag Doll (guest star Troy James) to kill Joe (Jesse L. Martin), Singh (guest star Patrick Sabongui) suggests he go into Witness Protection but Joe refuses to stop investigating Carver (guest star Eric Nenninger). While investigating Carver with Cisco (Carlos Valdes), Ralph (Hartley Sawyer) runs into Sue (guest star Natalie Dreyfuss). Iris (Candice Patton) becomes suspicious of Eva (guest star Efrat Dor). Alexandra La Roche directed the episode written by Kristen Kim & Thomas Pound (#616). Original airdate 4/7/2020.