Ian McKellen, Danny DeVito, and Sylvester Stallone will lend their voices to Animal Crackers, EW has confirmed.

Scott Christian Sava and Dean Lorey wrote the script for the film, which Sava and Tony Bancroft will direct. The story follows a family that inherits a rundown circus and a mysterious box of animal crackers. The crackers turn the people into the animals they eat, including lions, and tigers, and bears—oh my.

Patrick Warburton, Gilbert Gottfried, Raven Symone, Harvey Fierstein, James Arnold Taylor, Tara Strong, and Lydia Taylor round out the voice cast.

Sava is producing through his Blue Dream Studios alongside Storyoscopic Films’ George Lee and Marcus Englefield, voice/casting director Jamie Thomason, and Leiming Guan. The film is currently in production and is scheduled to be completed in summer 2016.