My plot theory...
Henry is an alien.
*Arguments: His appearence. -> The aliens (the man watching in the planet) have been watching Earths news and other programs and made the conclusion that politicians and rock stars are the most important people shown. That's why has he wears his suit and his hair is "what it is" imitating all the punk rockers.
(IMO, he looks like one of the Leningrad Cowboys! :D)
* The weird alien child. -> Obviously, it is theirs and just not something random that Lynch put to confuse us. And the opening scene, where one of the sperm things comes from his mouth I think meant that the child was made.
*Lady In The Elevator. She is his real wife and the sperms reflect that Henry could'nt put her pregnant and is now haunting him.
*Man In The Planet is Henry's father-in-law (Lady In The Elevators father) or just someone who is watching how he is doing on the Earth. (Mission leader, friend etc.)
I have no idea what the erasers are for and the ending either. :D
What do you think of my theory? Is it invalid? Well, after all, it's only a theory that can't never be proven to be false or real.
Any theories of your own?
As the title says.