In the flashback twenty years prior the gang meets Duddits as a young boy, he's already got super powers and disability and they become lifelong friends. Now our pal Morgan Freeman says he's been hunting aliens for twenty five years and when we meet Mr. Gay one of the first thing he does is start asking about Duddits. Mr. Gay is so interested in Duddits that when he finally hears Duddits in his head he stops the car he's driving, literally putting his plans for world destruction on hold just to marvel that he finally has a line on Duddits.
So here's my theory, Duddits and Mr. Gay are two members of slightly different species and maybe used to date.
Mr. Gay demonstrates that aliens can turn their bodies into a dust cloud at will to take over people's minds and not die, seeing as how Mr. Grey gets pulled back out of Homeland at the climax. So like, 30 some years ago Duddits, knowing that Mr. Gay is an asshole on a planetary scale, goes to Earth and finds the mentally weakest person he can find that has died and come back. In this case a sickly, handicapped child named Duddits and takes him over so he can stop Mr. Gay's.
Cut to the end of the movie. Duddits just lays there and takes it while Mr. Gay sticks his stinger into him. Then Duds flips the script and turns into a suspiciously similar looking alien as to what Mr. Gay's species looks like when they're bipedal (aside from color) and stabs Mr. Grey with a nearly identical stinger. Then they seem to melt into each other and then turn into a puff a red mist, which is what this species uses to spawn and has been established as nonlethal so I'm pretty sure that last scene of the movie is Duddits and Mr. Gay having sex.
If this is true, then this could also mean that the crashed "invasion" ship misted itself to avoid being shot instead of self destructing (which seems stupid if you're there to infect everyone with your presence anyway).
That movie made me mad and I never thought I would have to write the word Duddits that long.
