In the Steven Spielberg classic, E.T. The Extra-Terrestrial, the titular alien died before later coming back to life and making a full recovery—but why did E.T. die, and how did he get better? After E.T. was able to successfully phone home, he began to die in the forest. Michael managed to take E.T. back to Elliott, but when government agents took over the house and turned it into a quarantine facility, E.T. died. After Elliott was left alone with him, however, he returned to life and said that his people were returning for him.
Throughout E.T., which was originally scripted as a horror, the alien was connected to multiple living beings including Elliott and the geraniums. The connection was so strong that as he began to die, so did Elliott and the flowers. After being separated from the alien, Elliott managed to recover. The geraniums, on the other hand, died along with him. While Elliott was alone with the dead extra-terrestrial, both E.T. and the plant were revived and the alien said that the other extra-terrestrials were coming back for him. In the moments before he came back to life, his heart also began to glow.
One popular theory (via Stack Exchange) is that E.T. died because he was susceptible to Earth’s pathogens. The theory states that he was vulnerable to viruses and bacteria because he had DNA. This theory isn’t hard for viewers to entertain because pathogens have caused the death of alien visitors in multiple films, most notably another Steven Spielberg movie, War of the Worlds. The concept was even spoofed in Scary Movie 4. Other theories range from reliance on cold temperatures to breathing CO2. E.T. might’ve relied on carbon dioxide like a plant and was resurrected after being put in the cold chamber that appeared to use dry ice, which produces CO2.
Another theory focuses on his glowing heart. Rather than relying on a pathological explanation or recycling from other alien movies, the theory aligns with the film’s symbolism. The start of the movie showed audiences the extra-terrestrials were connected by something that made their hearts glow. This connection might have been what kept them alive, and the theory states that E.T. lost the connection while he was stranded. It logically follows that when his people returned, the repaired connection caused his heart to glow and brought him back to life, in the ending of the E.T. movie.
The symbolism found in the geraniums was an overt sign of E.T.’s connection to other living things. The flowers mysteriously moved around throughout the film and always aligned with his health. He could have intentionally attached himself to Elliott and the geraniums, knowing he relied on a connection to his peers to survive. Unfortunately, a connection to a flower and a human boy couldn’t sustain him. Audiences have also speculated that he created the connections intentionally. Elliott did not die, but the flower did, so he might’ve released his connection with Elliott in order to save his life.
He already showed he could reanimate flowers, but he might not have had that power with humans. Thankfully, he had contacted home, and when they arrived, his heart began to glow, and he and the still-connected flower were brought back to life. In E.T. The Extra-Terrestrial, which was the highest-grossing movie ever upon its release, the titular alien died because he was no longer connected to his people, but he got better after successfully phoning home because his family came back for him.