The initial fart sound effect and the woman's surprised reaction.

The video starts with a close-up of a smartphone screen displaying a 'Fart' app with a large green button. A finger taps the button, and a cartoon fart sound effect plays. The scene then shifts to a woman sitting on a couch, looking bored. The phone is brought near her, and the fart sound plays again, making her react with surprise and disgust. The app then switches to a 'Hair Clipper' sound effect. The phone is held near the back of the woman's head, and the hair clipper sound plays, causing her to jump and touch her hair in alarm. The video then shows a montage of various prank sound effects available in the app, such as 'Laugh', 'Whip', 'Gun', 'Chainsaw', 'Air Horn', 'Taser', 'Horror', 'Alien', 'Blow Nose', 'Break Glass', 'Toilet', 'Burp', 'Snore', 'Animal', 'Man Cough', 'Woman Cough', 'Scream', 'Scissors', 'Police', and 'Door Bell'. The final scene shows the app's icon and offers a 'Download Now' button, along with a 'Get it on Google Play' button.