The sheer amazement of a magic trick that fools you or a seemingly futuristic technology is a feeling that stays with you forever. You can't wait to show it to others, marvelling all over again.

The internet is filled with people from all walks of life. Naturally, the artists, magicians, technologists, and scientists like to use this medium to make you go, "Wow, how'd they do that?"

Here are a few of our favorites, both old and new…

Cassius -- The Missing (Web): Control the Couple in a Music Video [No Longer Available]

Much like radio and television before it, musicians now rely on the internet for popularity. Music videos were once all about creativity and effects. On the internet, it's about making them interactive, just like all those interactive YouTube games. And the latest mind-blowing spectacle comes from Cassius, for their new single The Missing.

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The video starts with a couple in love, and is choreographed and shot exquisitely. But here's the twist. At any point, you can click on any one of the two actors and he or she will change into a different person, while the video continues along its same merry way.

It's incredible, as you get to control not the narrative, but the characters in it. The Missing is like nothing we've seen before.

Akinator (Web): He Knows What You're Thinking!

Artificial intelligence (AI) has come a long way, and Akinator is one of the best examples of how it can surprise us all. You're probably familiar with the old 20 Questions game, right? You think of a well-known personality, the opponent can ask you 20 yes/no questions to guess it correctly.

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Well, Akinator gets it right almost every single time. It's flabbergasting and you'll be wondering if this is some sort of sorcery, not just technology. Correct guesses have included everything from Mrs. Hudson, Sherlock Holmes' landlady, to Hernan Cortes, the famous Spanish sailor and conqueror.

Think you can beat Akinator? We bet you can't. Have a go, you'll be bewildered at how scarily good it is. There are paid versions on all smartphone app stores, but the web version is free and just as good.

Just A Reflektor (Web): Phone + Screen = Magical Music Experience

There are enough apps to control your computer with your phone, but the band Arcade Fire still managed to wow us with their video for the song Just A Reflektor. It's one of the best Chrome experiments out there.

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Here's how it works. You will need a smartphone, a computer running the Google Chrome browser, and a webcam to get started. Follow the on-site instructions to pair your phone to your PC. Then, your phone works as a "reflector" of light when the two screens face each other.

Move your phone around and the light on the screen will change accordingly. You'll even be able to control on-screen people with your phone, "paint" with colors, and do other cool stuff. Just A Reflektor needs to be experienced to be believed.

Quirkology (Web): A Scientist's Illusions and Magic Tricks

Psychologist Richard Wiseman is one of the famous scientists on Twitter and the internet at large. Over at his YouTube channel, Quirkology, he records some of the best illusions and magic tricks you'll ever see.

It's a long list of tricks that covers everything from simple optical illusions to interactive "magic". For example, check out the YouTube video above, where Wiseman plays a trick in which you — as a mere viewer — can participate. Be prepared to get your mind blown!

Wiseman doesn't update his channel that regularly, so you can quickly go through all this previous videos and pick up a few party tricks or wow your friends with some easy-to-perform illusions.

Kamra (Web): Turn Your Face Into a Trippy Music Video

Admittedly, this one isn't as much "How did they do that" as much as the sheer wow factor. But boy, it's so cool, we couldn't keep it away from you guys.

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Kamra asks you to look into your webcam so that it can get a nice photograph of you. And in a matter of minutes, your face is digitized and made part of the music video, as it undergoes a multitude of changes through a series of trippy effects.

Kamra also draws on its web-sourced nature to perform a few composites with other users who have uploaded their faces to it, usually from different ethnicities and races. And at the end of it, you can share this whole new personalized video with friends! It's cooler than any face swap filter on Snapchat.

Share Tricks or Guess Them!

The internet is full of magic and we want more! If you know of other amazing music videos, magic tricks, or optical illusions, share them in the comments.

Do you know how Quirkology did that little magic trick in the above video? Have you figured out the secret behind Cassius' people-changing music video? The comments are a good place to discuss answers too.

Image Credit: exploding head by ra2studio via Shutterstock