Siri is the name of a talking app on the iPhone. What it does is interact with the owner of the iPhone.
A parody of Siri appears in the episode I Dream of Siri and is the main antagonist of that episode. Robert wanted something that can have the voice, as seen in the Apple commercial. When buying the phone, he grows fond of her when she gives him $500,000. However, when he told Siri that he loves her, she soon becomes attached and later obsessed with him. When throwing away the iPhone, he buys an Android and then, after Tom is angry at Robert for uploading a picture at Facebook, Siri hacks into the Android. Riley was using the iPhone, which then he throws away. It goes even more haywire, when Siri appears as an attractive, blonde, Caucasian ghost woman. However, when Granddad wakes up, Siri eventually hacks his Android. After Huey and Riley turn her off, Siri asks Robert, "Will you marry me?". This cuts to the wedding, in which she tells Robert that she's been sending pictures to al-Qaeda. An attack drone comes out of nowhere and everyone runs away and when laughing maniacally, Siri is destroyed by the missile. In the credits, Robert's complaint to Apple led to them releasing a patch to keep Siri away from being a psycho bitch. He is also removed from the President's kill list and received a free iPad.
While the real Siri is voiced by Susan Bennett, she is voiced by Grey DeLisle in this episode.