|First Appearance:|| It's Walky! 25 March 2004|
As the Martian invasion began, SEMME sent Squadron 37 to retrieve the Anti-Head Alien from the Triangle, hoping to gain access to the original Hed Alien's memories. Despite losing most of her team to a zombiefied Hooper, Lith was able to rescue AHA and return him to SEMME custody.
During the final confrontation with the Martian invasion force, Head Alien's soul possessed and took control of Anti-Head Alien using The Cheese. It is unclear whether any part of Anti-Head Alien remained after this possession, but it would seem to be a moot point; after The Cheese was released from Head Alien's control, Sal impaled him with a Martian fork, killing him.