Donald Davenport created Eddy to be his home security system, and it was implied he used to be kind and helpful. However, Eddy ended up becoming mean and unforgiving over time to the point to becoming spiteful and unhelpful.
After Donald married Tasha, Eddy constantly had it out for Tasha, and showed great hate for her son, Leo Dooley. Even Adam, Bree and Chase started seeing Eddy as the bane of their existence.
During Donald's and Tasha's one year anniversary, Eddy was angered because it was on the same day as his activation. In retaliation, Eddy would antagonize Tasha by messing up her anniversary pictures, and insulting her even when he was told to apologize. Later, Tasha forces Eddy to comply with giving her control of his mute button, and tricks him by saying she will talk Donald into not shutting him off the next day as he was about to get shut down for the night.
During a contest in Tech Town, Chase uses a previous version of Eddy, which he calls "Cheddy". The app proved to be useful until Eddy broke out of the app, and terrorized everyone's phones and all the computers in Tech Town. Chase was forced to shut down Eddy through his mainframe.
When Tasha was sick, Leo created a diagnostic pill that was based off of his schematics. However, Leo ended up downloading Eddy into the pill, causing Eddy to possess Tasha. Eddy once again antagonized Tasha by dressing her up in a ridiculous fashion and making enemies of all of Tasha's friends.
Eddy eventually hacked into the Davenport Bionic Academy's computers, and began insulting everyone again. Perry however, took a liking for Eddy because of their similar personalities, and Eddy felt the same way. Donald eventually gave Eddy an android body to help Perry out and made him nice. However, Perry was disgusted at his new personality and reverted him back to his original personality. Because of this, Human Eddy began insulting Leo and terrorizing the kids by trapping them in walls as revenge for the way they treated him in the past. Eddy even manipulated the security footage so Donald wouldn't believe the kids. The kids decide to get Perry and Eddy to fight each other, though Eddy ended up insulting Perry anyways. During the fight, kids do everything they can to defeat him, but nothing could harm him. The Lab Rats later find out that Perry undid Eddy's kindness. The moment Eddy spouted hurtful words about Davenport, it became the final straw for Donald, who came out and revealed he overheard the whole fight. Donald put his foot down and decided to punish Eddy by sending him back on the wall. Eddy resisted by attempting to destroy the tablet that would control him. Despite his protests, false promises, and resistance he put up, Perry blasted Eddy to bits. Eddy was reduced back to being an emoticon, permanently imprisoned in the Academy's wall-screens.