Sheila

"Hello, and thank you for activating the M808V Main Battle Tank. You may call me Sheila."

- Sheila's first line in Check Out the Treads on That Tank

Sheila, originally named F.I.L.S.S., is the vehicle-only AI behind the Blue Team's Scorpion tank built by an American automotive company and assembled in Mexico. She's a main supporting character in the Blood Gulch Chronicles and a minor character in the Recollections.

Overview
Sheila is a product of the military contractor that made the lowest bid, something she is ashamed of. When she first appeared, Sheila acted like an ordinary tutorial program, showing little emotion. However, in Season 2, Sheila developed a sense of kindness. Sheila is based on F.I.L.S.S. as both not only have similar personalities and voices, but Sheila's original name was Phyllis (F.I.L.S.S.) before Church changed it. Currently, she is still active at Valhalla in a airship, but is running at minimum capacity.

Deployment In Blood Gulch
Sheila first appeared in Episode 3 with fellow Blue Team member Caboose. She is friendly and cheerful but, being a tank, has a habit of blowing people up, including her own teammate Church. Sheila is bombed out of action by Sarge's dropship early in the first season but is repaired by Tex several episodes later. Donut later disables her again by pitching a plasma grenade halfway across the canyon into her cockpit at the end of Season 1.

Sheila shows some indications of liking Caboose early in Season 1. However, in the middle of Season 2, she falls in love with the Red Team's robot, Lopez. Before long, the two attempt to lead a robot revolution against the humans in response to perceived abuse that they have received: being constantly blown up or possessed by ghosts. This idea stemmed from Church's attempt to prevent them from doing so during his time-traveling endeavors to stop Lopez from creating a vehicle, which would later be stolen and used by O'Malley. After O'Malley kidnaps Lopez, however, Sheila puts aside her differences in order to help the soldiers retrieve him.

Because Sheila cannot fit through the teleporter (due to the fact that her AI was hardwired into the tank by her manufacturers), she remains behind on Blood Gulch while the Reds and Blues leave to pursue O'Malley. After a brief encounter with a time-traveling Church, who whispers a plan to her, Sheila powers down and presumably remains alone as the sole inhabitant of Blood Gulch for the better part of a millennium. It is thought that she may be the source of the distress signal that the Reds hear in Season 3, as Church's plan included the words "a thousand years." A deleted scene on the Season 4 DVD confirms that she is ordered to send out the distress signal and disguised her voice.

Alone
Upon their return to Blood Gulch, all of the Reds except Sarge see her drive past the Red Base. When Sarge demotes Simmons for his talk of "imaginary" tanks, she helps him attempt his revenge on the Reds since she is unable to recognize them as her enemies due to a faltering memory unit. She also expresses dissatisfaction when Church later collects all the vehicles available to the Blue Base in Blood Gulch; Church perceives her reaction as jealousy (this scene was relocated to the Deleted Scenes section of the Season 4 DVD for continuity reasons).

Later in Season 5, Church brought Sheila along to claim the dropship which had just landed, but Sheila then deserted Church, forcing him to give up the ship to the Reds. Church noticed that Sheila was acting oddly (conveniently around the time that Omega left Doc) so, in Episode 85, he sent Doc along to try and help the tank calm down. However, it quickly became clear that his methods were not very effective on tanks.

Later, Doc reported back to Church, concluding that something was wrong with her. Church decided to look for "somebody sneaky to turn her off," and they eventually decided to send Caboose. They went to Tex to explain the plan and asked her to access the panel to shut Sheila down while Caboose distracted her. In Episode 91, Caboose began to distract Sheila, albeit with Church's inane help, and asked Sheila where the Omega AI was located. However, just before Sheila could reveal the information, she was shut down by Tex. Caboose revealed to Tex and Church that Sheila knew who was Omega's new host so they attempted to look for a similar mechanical body, as the tank was too damaged. They decided to move her into the dropship that had arrived earlier.

Transfer to the Ship
In Episode 95, Sheila was activated on the ship, discovering that a missing ignition coil had been behind her malfunction. She then told Caboose that Omega's new host was the Blue's leader. Caboose figured that it was Church when the real host was Captain Flowers. In the last few episodes of The Blood Gulch Chronicles, Tex, now with Omega, the Other Alien, Junior, and Wyoming's helmet boarded Sheila's ship and took off. However, unbeknownst to them, Sarge had previously loaded Andy onto the ship. Shortly after takeoff, Sarge ordered Andy to detonate and the ship seemingly exploded, leaving everybody on board presumably dead. This, however, is later proven false.

Crash Landing in Valhalla
In Reconstruction, it is revealed that Andy had only partially exploded and the ship had crash-landed in Valhalla. In Chapter 5, Washington, Caboose, and Church find that Sheila survived the ship's crash but sustained extreme damage in the process. Nonetheless, she is able to replay the recordings of the crash. It is possible that the damage she was referring to was hardware damage, since she had previously stated that she was not functioning at full capacity while still inhabiting the tank.

In New and Improved, Epsilon was inserted into the ship by agent Carolina in the hopes of recovering any information on the Director. Epsilon refers to Sheila as "an old friend" and mentions she is actively trying to help him access the available data, proving that while inactive, at the very least she still functions.

Personality
Although she is (commonly) a tank, Sheila has been shown to be kind and gentle throughout the series. While several characters easily go into a panic when seeing her, Sheila is usually calm as she easily gets along with others and keeps a consistent tone throughout. Sheila is also very caring, as she was able to help the unstable Simmons from commiting suicide after his demotion. However, she enjoys blowing things up (mostly Church), continued to call Tucker a retard in Me, Myself and You, and helped Tex/O'Malley leave Blood Gulch.

Relationships
Despite being one of the original characters in the series, Sheila hasn't developed many relationships. However, she has developed some strong relationships with certain characters.

Church
After being killed by Sheila in the first season, Church shows a slight hatred toward her and annoyance. At one point he forgave her while she was sorry for enjoying it so much, possibly making their relationship worse. It seems that shooting Church relaxes her, as when Doc asked her, she aimed her cannon at him, scaring him. Church has told Caboose even if Sheila fired at him, the shell would most likely reflect off Caboose and hit him instead.

Caboose
Caboose first meets Sheila in Episode 7 and has been attached to her ever since. In Season 2, Caboose was jealous of Lopez for having a relationship with Sheila. In Season 5, Sheila shows concern for Caboose when he acted "odd", and telling him to not do so or others would think he had the Omega A.I. (ironically others thought the same of her at the same time). When Caboose re-encounters Sheila in Reconstruction Chapter 5 after she crashed in Vahalla, he is happy to see her and asks if she is okay. He later gets mad when Washington talks to Sheila like a program and not a person, telling Wash, "Don't talk to her like that! She is not a program," thus showing that he still has strong feelings for Sheila.

Tex
Though they are shown to interact very little, the two get along quite well. Tex was able to fix Sheila after Sarge's air strike and after many members leave to chase O'Malley/Doc, the two discussed the boys' "dirty" ideas. Even when Tex was possessd by Omega, she still helped her escape in order to end the Great War.

Simmons
Sheila and Simmons seem to have a decent relationship with each other, during their time in Season 4. After Simmons was demoted, Sheila cheered him up, preventing him to commit suicide, and have him joined Blue team with her to get payback against the Reds. Sheila was against Church on abusing him when he returned as well.

Lopez
Lopez started his relationship with Sheila in Episode 29 after fixing her. They were immediately attracted to one another, sparking jealousy from Caboose, which was increased because he was occupied by the Omega AI at the time. Lopez's relationship was delayed because Tex came back and possessed Lopez's body to pursue Omega in Caboose. In Episode 36, Lopez and Sheila went off to build a robot army, which was inadvertently proposed by Church when he went back in time. In Episode 38, O'Malley took Lopez as a hostage. He and Sheila did not have much of a relationship after that.

Romance
After Sheila was activated in Season 1, Caboose fell in love with her and Sheila showed similar feelings to Caboose, but upon meeting Lopez she immediately fell in love with him. Since then, this love triangle has become a running gag as Caboose will do anything to achieve Sheila's compassion, with other characters pointing out how odd it is. After Junior was born, Church even stated that he didn't want to risk having "Junior Caboose with a cannon for a head," by sending Caboose to find out what was wrong with Sheila in Season 5.

Abuse
Sheila has taken much abuse since she was activated. In the first season she was blown up twice, she was left alone in Blood Gulch in You're the Bomb, Yo, and in Season 5 she was tricked & deactivated by her own team and after being downloaded to the ship, Andy detonated onboard when she was leaving Blood Gulch which damaged her greatly. This was also one of the reasons why she decided to form a robot army with Lopez.

Tank
When she was a tank, Sheila was extremely powerful, as her canon is strong enough to destroy entire vehicles and kill any character with one hit if taken directly. Along with this, she was very durable, as she could take immense damage before becoming inactive, as it took an airstrike and a well thrown plasma grenade to stop her. Even if this body becomes too damaged to operate, she can still be downloaded into a large enough vehicle to continue on.

Pelican
As a Pelican, Sheila wasn't only as strong as her original body, but had increased maneuverability, allowing her access to areas she couldn't before. She also showed that while at full functional capacity, she could create firewalls and trap other A.I. in them, such as Gamma. Although she is still active in this form she can only operate at minimum capacity.

Trivia

 * Sheila is the first female character to appear in the series.
 * In the sponsor videos, Washington says that Sheila is a "smart" tank, which is a rare occurence. This explains why the Blues in Rat's Nest thought it was weird and abnormal that Caboose talked to vehicles.
 * It was confirmed at Comic-Con 2010 that Sheila would return in Season 9. However, she did not have any dialogue.
 * Sheila might be bi-curious, as she becomes confused by Lopez getting possessed by Tex right after they fall in love, stating that her wires felt crossed and admitting that she liked it.
 * Rooster Teeth stated that Andy was originally meant to be Sheila's ex-boyfriend. However, the idea was pushed to Season 5, along with, according to Hullum, "a really interesting character trait related to that Andy's relationship with Sheila."
 * In S.O.S., Freckles says "Firing main cannons," which is a reference to Sheila whenever she attacks, as she makes the same statement.