If you're looking to prank someone remotely, you can 'bomb' their phone by spamming it with a series of random or meaningless messages as quickly as possible. Here's how you can create a message overload for someone else.
Steps
Choose the target for the message bomb

Choose someone with an unlimited messaging plan. If you send 100 messages to someone with a limited plan, they will be furious when they see their phone bill. It won't take long for them to trace back the prankster, and you’ll find yourself in trouble. You may even have to pay for the extra charges yourself.

Choose someone you often have fun with. Surely, you wouldn't want to spam the messages of someone too sensitive or easily angered. Pick someone who you can joke with, and although they might get annoyed, in the end, they'll find it funny or quickly forgive you.

Don't use message bombing as a threat to others. Tracing the culprit is not difficult, and you might face serious consequences. The victim of the message bombardment could report the harassment, and you might even find yourself in court over it.
Manually send the message bomb

Open the messaging app and select the recipient from your contacts. Wait for the right moment when you know they are engaged in something important, like a date or work, and they have to keep their phone with them.

Send random messages, letters, or emojis. This is a super-fast way to spam messages. Place your thumb lightly on the "send" button and use your other thumb to randomly press letters, numbers, symbols, or emojis.
- Alternate between the two thumbs, quickly composing a message with one and pressing send with the other, just like you're playing a video game.
- Send as many messages as possible for as long as you can. The longer you bombard the messages, the more annoyed the recipient will get.

Send more messages by texting one word at a time. If you really want to convey something instead of just trying to send meaningless messages, break down the content and text one word at a time. Don't worry about spelling, what you need is to type and send as fast as you can.
- You can try sending the lyrics of a song one word at a time.
- Send the same word over and over. Awaken your inner 2-year-old by constantly responding to everything they text with "why?"
- If you're sending identical messages repeatedly, save time by copying and pasting into the text box instead of typing it every time.

Block their number. To prevent retaliation, you can temporarily block their number. The victim will get even more frustrated when they realize they can't text back to scold you or retaliate with another round of message bombing.
Bomb the messages using an app

Use websites to prank your friends. Many websites allow you to enter a phone number, message, and the number of times you want the message sent. Then, the website will do the 'dirty work' by sending hundreds of text messages to that number on your behalf.

Find message bombing apps for your phone. Many message bombing apps have been removed from stores due to user complaints, so it is hard to find an effective one with reasonable cost.
Warning
- The victim may truly get upset if you take the joke too far. Consider the consequences carefully before starting to message bomb anyone.
- Message bombing with the intent to harass could be considered illegal behavior. Only message bomb your friends as a prank. Never repeatedly attack someone with mass messages or any other means.
Things you will need
- Mobile phone
- Unlimited text messaging plan