You shouldn't have to wait until April Fools' Day to prank your friends. These five hilarious tech pranks are sure to make your friends scratch their heads. Do note that we're using a Samsung Galaxy phone, but most of these pranks can be done on any Android phone. Let's begin.

1. Slow Down Your Friend's Phone

The first prank is to make their phone incredibly slow to the point where it's absurd. One way to do this is by slowing down device animations. Follow these steps:

  1. Go to Settings > About phone > Software information and repeatedly tap Build number to enable Developer options.
  2. Go back to Settings > Developer options and set Window animation scale, Transition animation scale, and Animator duration scale to 10x.

You can also slow down their device by making their phone require an absurdly long time to register a long-press. We do this by increasing touch and hold delay. Follow these steps:

  1. Go to Settings > Accessibility > Interaction and dexterity > Touch and hold delay and tap Custom.
  2. Tap and hold for at least five seconds. The longer you hold, the more trouble you create for your friend. Once done, tap Save.

Do note that not all Android phones allow setting custom touch and hold delay, so this prank may or may not work on your friend's device.

2. Mess Up the User Interface

The next prank is to mess up the user interface of their phone. There are a number of ways to do this. For instance, you can invert system colors, set a random color correction mode, and increase font size to a ridiculous extent. Here's how to do all this:

  1. Go to Settings > Accessibility > Visibility enhancements and toggle on Color inversion.
  2. Go to Color correction, toggle on the feature, and select any random correction mode.
  3. Go back and scroll down to find Font size and style and drag the slider all the way to the right. You can also toggle on Bold font and change the font style to something random.

You can also customize the Quick Settings panel in a random order, like so:

  1. Swipe down from the status bar and swipe again to see the full page.
  2. Go to the last page and tap the Add (+) button.
  3. Drag the icons to random locations; you can also add more buttons from the top to make it more confusing.

You can even hide their favorite apps from the app drawer by going to Settings > Home screen > Hide apps and selecting their most used apps and tapping Done.

And just in case you're feeling extra naughty, you can also make the app icons tiny so they're hard to see. Third-party Android launchers usually have an option to change app icon shapes and sizes, but they also change the look of the UI, so your friend might immediately spot what's wrong.

On Samsung phones, however, you can do this with the Good Lock customization app which preserves the look and feel of One UI, so your friend will never know what went wrong. Follow these steps to perform this prank on Samsung phones:

  1. Download the Good Lock (free with in-app purchases) app and install the Theme Park module.
  2. In Theme Park, go to the Icon menu and tap Create New.
  3. Tap the down arrow and drag the Size slider all the way to the left.
    • You can also change the shape and color of the icons to something random.
  4. Tap the Install button at the top and give this theme a name and tap OK.
  5. Go back, open the new theme, and tap Apply.

You can also apply icon packs and set incorrect icons for all their apps.

3. Spam Their Phone With Your Funny Selfies

While you're making a mess of your friend's phone, why not also spam your funny selfies in it? Here are three ways to do this which we like the best.

Firstly, set your funny selfie as their contacts' profile picture:

  1. Take a selfie (preferably while making a face) using your friend's phone.
  2. Go to the Contacts app and select a contact.
  3. Tap Edit and tap the profile picture, then select Gallery.
  4. Find and select your selfie, crop it, and tap Done to set it as the new profile picture.
  5. Do the same for all of their favorite contacts.

Next, set your funny selfie as their video call background image:

  1. Go to Settings > Advanced features > Video calls effects.
  2. Toggle on the feature and tap the Add (+) button under Background image.
  3. Find and select your selfie, and tap Done.

Lastly, set your funny selfie as their Gboard theme:

  1. Open the Gboard app to access Settings, then go to Theme and tap the Add icon under My themes.
  2. Find and select your selfie, then position your face in the frame and tap Next.
  3. Set the brightness slider to 100% and tap Done.

And you're done! As soon as they begin typing, get a call, or accept a video call, they'll see you making a face—greeting them hello in the funniest way possible.

4. Mess Up the Audio and Calls

So far, you've screwed up their device animations, app icons, system colors, background images, and more. To add a cherry on top of this, you can mess up their audio and calls.

To do this, go to Settings > Accessibility > Hearing enhancements and turn the Connected audio slider all the way to the left or right to create a sound imbalance while listening through headphones. You can also toggle on Mute all sounds instead so they can't hear anything.

You can also go to Settings > Privacy and toggle off Microphone access so they think their mic is broken. You can also swap contact names in the Contacts app; they'll inevitably find out about it, but seeing their initial panic of calling the wrong person is more than worth it.

5. Rename Paired Devices

Go to Settings > Connections > Bluetooth and toggle it on. You'll see a list of their paired devices. Tap on the settings icon and tap Rename. From here, you can let your creative loose and think of all sorts of funny names for their earbuds, smartwatch, and other paired devices.

For instance, you can rename their earbuds as "Peer Pressure Pods" and their smartwatch as "Low-Battery Belt" or something similar.

Android Pranks to Mess With Your Friends

You can use all these pranks to have some harmless fun with your friends, but do make sure to reverse all of these settings after you're done making a fool of them so their phone starts working like normal again.