Bug Filter Prank

Hand someone your phone and watch a cockroach bolt across the screen.

Bug Filter Prank puts believable insects on your phone: crawling on a blank screen, on top of whatever app is open, or on whatever your camera is pointed at. Every bug is drawn frame by frame with its own gait, its own pauses and its own contact shadow, so it moves like something alive instead of a sticker sliding around.

THREE WAYS TO PRANK

On this screen

A blank screen with bugs loose on it. Set a head start, hand the phone across, and wait. Press and hold for two seconds to stop it, so the first startled swipe does not end the joke.

Over other apps

The bugs crawl on top of the home screen, a chat, a video, anything. The phone keeps working normally underneath, which is exactly what makes people brush at the glass instead of closing an app.

Camera filter

Point the camera and the bugs land on whatever you see: a plate of food, a wall, a friend's shoulder. Tap the shutter and the photo is saved with the bugs exactly where they were on screen.

EIGHT INSECTS, EACH WITH ITS OWN BEHAVIOUR

Cockroach, black ant, house spider, housefly, mosquito, ground beetle, caterpillar and bed bug. The roach bolts and freezes. The spider dashes then holds still. The fly walks, takes off and lands somewhere else. The caterpillar bunches and stretches. Pick which ones turn up, how many there are, and how fast they move.

IT IS THE MOVEMENT THAT SELLS IT

A bug that slides across the screen at a constant speed fools nobody. These start and stop, change direction, pause for a moment and then bolt. Each one is drawn at its true size, from a five millimetre ant to a thirty millimetre roach, and each one casts a small shadow on the glass. Turn on "bugs run from your finger" and they scatter when the screen is touched, which is usually the moment the person realises they have been had.

A HEAD START THAT ACTUALLY HELPS

Choose a delay of five seconds, ten, thirty or a minute before the bugs appear. That is enough time to unlock the phone, open the prank and pass it over without giving anything away.

ALSO IN THE APP

Light and dark themes, with light being the more convincing prank on a bright screen. A bug catalogue listing the real size and behaviour of each insect. Saved captures from the camera filter, kept in one place.

PLEASE PRANK KINDLY

This is a joke app. The insects are not real, nothing is wrong with the phone, and nothing is being damaged. Please do not use it on anyone with a genuine phobia of insects, on children, or on someone who is driving or otherwise busy. The best pranks end with everyone laughing.

The "over other apps" mode asks for permission to draw over other apps, and the camera filter asks for camera access. Both are only used for what they say, and both are optional.