Ever glimpsed something and then had to a double take? A bit like the people who snapped and shared these photos?
Some sights can really mess with our brains as we try to figure out if what we're seeing is "really there".
From funny to weird, every one loves a good optical illusion, just check out these 20 photos and see which ones leave you really confused!
1. Having a serious conversation with his "TV self"

© npc48837 / reddit
2. Built in binoculars

© RaW2DaFlooR / imgur
3. Reflective or transparent?

© carrotsaregreat / reddit
4. From another dimension

© B-L-O-C-K-S/ reddit
5. A chicken with a really long neck?

© wombatfer / reddit
6. When a branch morphs into a snake

© Yosho2k / reddit
7. We seriously hope this is on the side-view mirror and not the ceiling

© hrshelley / reddit
8. A wall with veins or just the cables' shadows

© SmartFridge369 / reddit
9. Two cats merge into one

© AppleNatives / reddit
10. Don't panic, it's just a cloud

© Hool-E / reddit
11. When a camera glitch creates a day vs nighttime effect

© Lance2boogaloo / reddit
12. Self-mixing popcorn

© aMac_UK / reddit
13. A natural car protector

© Zee-J- / reddit
14. When a birthmark makes a statement

© Epitomeofabnormal / reddit
15. The power of a simple sticker

© brianjackson / reddit
16. When a key turns transparent

© NamesZacNotZach / reddit
17. How many people have marched into this mirror?

© Soo75 / reddit
18. When you just take one half of your dog for a walk

© Boggandy / reddit