Phineas & Ferb: Arkham Knight

Phineas & Ferb: Arkham Knight will be an comedy, musical, action adventure crossover story arc which will feature Phineas & Ferb and characters from Rocksteady's Batman: Arkham franchise. Kevin Conroy, Troy Baker, Tara Strong and more will reprise their roles from the titular series. The show will feature three episodes written by Paul Dini.

Synopsis
After the events of Phineas & Ferb: Mission Marvel, Doctor Doofenshmirtz re tests his De Powerinator on Batman (Kevin Conroy), but finds out that the Inator doesn't work on humans. Doof then teams up with the Arkham rogue gallery to take down the Batman once and for all. Meanwhile, the Bat family must seek help from Phineas, Ferb and Agent P, who are ready to take on the villains.