The Return (S03E11)

As they cruise down a Florida highway, a bus filled with escaped convicts crashes into their RV. Ben accidentally shifts into Stinkfly and attempts to intervene. With Grandpa's impressive driving skills and a magical spell from Gwen, they manage to recapture the felons. Later, the Tennysons catch a news report about purple lightning causing delays for a space shuttle launch. Remembering the same lightning from their encounters with werewolf and mummy aliens, they rush to Cape Canaveral. At the Space Center, Ben faces off against the werewolf, the mummy aliens, and a new Frankenstein alien. What’s causing the purple lightning, and how is it connected to an old acquaintance?