this is more of an opinion question, seeing as 1,000,880 aliens haven't even been shown in the series. personally, i think it's ether upgrade or big chill.
No
THE best alien of ben-10 ultimate alien is alien x.
queen alien is the best
normal Ben's best alien is ghost freak and benten alien forces best alien is gloop.
There were four Alien movies made: Alien(1979), Aliens (1986), Alien 3 (1992), and Alien Resurrection (1997). The sequel "Aliens" received the best reviews.
In my opinion, the first Alien.
4 arms is the best because hese the strongest alien
See a doctor... its always the best way (;
the best time to see an alien is at 2:03:54:009 am on feb the 29th 2010
The cast of My Best Friend Was an Alien - 2010 includes: Mona Waserman as Alanna Roddy
its either Ultimate Humoungousaur or Ultimate XLR8. EDIT BY UNDEADAWE: XLR8 cant go ultimate, lol. Anyways, Ultimate Ben is the best, fact, not opinion.
If you are looking information on what would be a good alien costume for Halloween, the best site is on costumezone.com/, they will give you the best costumes.