Rob Riggle, Brian Posehn and Kumail Nanjiani have joined the cast of the stop-motion animation laffer “Hell & Back” starring T.J. Miller and Nick Swardson.Tom Gianas and Ross Shuman will helm. Story revolves around two best friends who must rescue their buddy when he’s accidentally dragged to hell. Riggle will play a 20-year old who’s starting to grow up, much to the chagrin of his friends Augie and Remy. Posehn will portray an aging heavy-metal fan stuck in the ’80s and Nanjiani will play Sal the Demon, an employee of hell. Corey Campodonico, Eric Blyler and Alex Bulkley are producing through their ShadowMachine banner. Riggle can be seen next in Universal’s “Dr. Seuss’ The Lorax” and Sony’s “21 Jump Street.” Posehn can be seen next in Universal’s “The Five-Year Engagement.” Riggle is repped by CAA, Principato-Young Entertainment and attorney Warren Dern. Posehn is repped by Generate. Nanjiani is repped by ICM and Mosaic.