How do the heroes kill Enceladus?

Jason manages to few hit Enceladus with his spear, but Enceladus is too quick and strong for him and breaks Jason's spear, which explodes in a burst of heat and light, knocking them both backwards. Enceladus gets back up and prepares to kill Jason, but Leo hits the giant with a hydraulic axe. However, Enceladus just heals himself, explaining that the giants can only be killed by the combined strength of gods and heroes. This gives Jason an idea. Climbing onto Enceladus' neck, he begs his father for help, and is hit by lightning. It blasts him and the giant apart and creates a chasm in the earth. Enceladus falls in, but Leo and Piper throw a rope to Jason to pull him up.