As games got bigger, developers thrived on adding random fun stuff into them, like cheat codes that did one thing or another, or hidden features that players had to find. While some series offer more of them than others, few are as intriguing as the Easter Eggs in Metal Gear.

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Each game has produced so many interesting, funny, and even shocking things that tracking them down was part of the fun. There are more than enough, so this is just the tip of the iceberg for Metal Gear’s best Easter Eggs.

10 Cardboard Box Fast Travel

Metal Gear Easter Eggs- MG2 Cardboard Box Fast Travel

The cardboard box has been a staple item since the first game, but it wasn’t until Metal Gear 2: Solid Snake that it could do more than fool guards and cameras. Zanzibar Land had a series of conveyor belts that would transport supplies. If Snake equips the right box, he can post himself to different sections of the game.

This feature would return in Metal Gear Solid, where equipping a box in the trucks would take Snake all over Shadow Moses. Players could do the same in Metal Gear Solid 3, while they had to take invoices from orange platforms to open a base up for delivery in Metal Gear Solid 5. Only Metal Gear Solid 2 brought back the conveyor belt system.

9 Psycho Mantis Reads The Memory Card

Metal Gear Easter Eggs- MGS1 Twin Snakes Mantis Mario Sunshine

Breaking the 4th wall is part of Metal Gear’s formula, from the MSX cartridge in MG2, to Meryl’s codec on the back of the MGS1 case. The most famous example is Psycho Mantis reading the player’s memory cards. On the original PS1 game, he’d comment on the player's saves for Castlevania: Symphony of the Night, Suikoden, Azure Dreams, and Vandal Hearts.

The Japanese edition would also include Tokimeki Memorial, Snatcher, and Policenauts, where Hideo Kojima himself would thank the player for having the latter two saves together. While the Gamecube remake The Twin Snakes would see Mantis react to Super Mario Sunshine, Super Smash Bros Melee, The Legend of Zelda: The Wind Waker, and Eternal Darkness.

8 Ghosts On The Battlefield

Metal Gear Easter Eggs- MGS1 Photo Ghost

MGS1 had a digital camera item where players could snap pics from Snake’s POV. It was like a precursor to the Photo Mode in games today. But if players had room to spare on their memory card, they could take multiple photos and find some spooky surprises along the way.

Related: Metal Gear Solid's Best Fourth Wall Breaking Moments

The game’s developers would turn up as ghosts in the right places, usually doing something goofy. Like producer Yuji Korekado standing with a Super Saiyan-like aura in the men’s bathroom, or Hideo Kojima himself crawling out of the Policenauts poster in Otacon’s lab.

7 Photo Fun With Otacon

Metal Gear Easter Eggs- MGS2 Otacon Photos

Only one photo ghost returns for MGS2: Hideo Kojima on the projector screen in the Tanker. Send it to Otacon to give him a fright. That’s not the only picture he’ll react to either. Sending him photos of the girly posters will make him blush and save a copy for himself. Do it with the muscle man poster before the Engine Room, and he’ll think it “explains a lot” about Snake.

He won’t be happy with photos of Commandant Scott Dolph either, accusing Snake of being “a fan”. Yet he’ll giggle his socks off if he gets a shot of the Marines in their boxer shorts. To scare him again, climb up the ladder from the first floor on the right side of the last room, and look near RAY's leg to find Ocelot. Snap his picture before he disappears, and Otacon will freak out.

6 End The End Early Or Late

Metal Gear Easter Eggs- MGS3 The End Old Age Death Radio

The End is more of an obstacle as his shots will only knock Snake out. Lose all stamina? He’ll drop Snake off at the jail in Granin’s lab. Save the game to resume later? He’ll zonk Snake instantly on reload, then dump him back in the cell. The only way to beat him is to fight fairly, or be a sneaky cheat.

If players get the SVD rifle, they can kill the End at the port with a well-placed headshot. This will replace his boss fight with comparatively simpler Ocelot guards. But if the player’s stuck against him, they can save, wait 6 days (or set their console clock forward), then reload to make The End die of old age.

5 The Sorrow Lingers

Metal Gear Easter Eggs- MGS3 The Sorrow Secret Cutscene

During cutscenes, players can press R1 to see the scene from Snake's POV. Usually they'll be prompted, but there are some secret R1 scenes too. Holding it after Ocelot talks to Tatyana will see her mock his pointy-fingers gesture. Doing it when he leaves the Torture Room will see The Boss do the same. A lot of them involve The Sorrow, the COBRA Unit member who died before the game's events.

Related: Ranking Every Game in the Main Metal Gear Franchise

Holding it at the end of the Virtuous Mission will reveal his body at the bottom of the river. Doing it at the port will see him shadowing The Boss as she calls to him. He'll tease Snake with the bomb's timer if players hold the button during Volgin's long exposition on his motives, and doing so after killing The Boss will see the two depart from the mortal realm.

4 Make The Beauties Dance

Metal Gear Easter Eggs- MGS4 Dancing Raven

Metal Gear Solid 4’s Beauty & The Beast Corps aren’t usually most fans’ favorite boss troupe.They have little personality beyond their gimmicks, as their true "Beauty" selves all have the same MO of stalking Snake for a life-draining hug. They're pretty simple to deal with: just shoot them with more bullets or tranquilizer rounds until they fall.

But if the player stretches the fight out, they'll get transported to a white void. If they play “Oishii Two-Han Seikatsu” by Two-Han Princess on their iPod, the Beauties will do a dance to the opening chorus. One of the Two-Han Princess duo is Yumi Kikuchi, the model and Japanese VA for Raging Raven, so it’s only fitting to see her strut her stuff.

3 Date Paz And Miller

Metal Gear Easter Eggs- PW Love Box

Peace Walker’s true fun lies in its Extra Ops. They offer fresh battles against bosses, chances to grab extra tanks, or fight Rathalos and Tigrex from Monster Hunter. That, and dating both Paz and Master Miller. Big Boss has to dress well and use the right Co-op Comms to raise their heart points.

If they upset both too much, they’ll trigger a funny Game Over screen (“Paz! I’m sorry! Don’t walk away! Paz?! PAAAAZZZ!!”). But they can check their heart points by aiming the camera at them. If they do a little pose ("Make sure you get a good shot of my muscles!"), they're ready for the Love Box. Equip it and, if they pop inside for a shuffle, the mission is accomplished.

2 Déjà Vu

Metal Gear Easter Eggs- GZ Moai Head

Originally a PS4-exclusive mission for Ground Zeroes, this mission is essentially one big Easter Egg hunt. The player has to find all the callbacks to MGS1, then escape to pass the mission. If they're successful, Miller will then challenge them to a quiz, all while copying Liquid, Ocelot, and others. The questions can be pretty tricky too, like what the weight limit on the Comm Tower elevator is (650lbs).

Related: Metal Gear Solid 5: Ground Zeroes Conspiracy Theory

The callbacks include chucking a grenade into a tank, and switching off the power to bring up Psycho Mantis ("Black out!"). S-Ranking the mission will unlock MGS1 Solid Snake, and replace the guards with the Genome soldiers, and the hostages with the DARPA chief and ARMSTech President.

1 Jamais Vu

Metal Gear Easter Eggs- GZ Jamais Vu Raiden

Before this mission went multi-format, Jamais Vu was what the Xbox One got with Ground Zeroes over Déjà Vu. It’s named after the state where people find something or someone unfamiliar despite knowing them well. In this case, they recognize Raiden from Metal Gear Rising: Revengeance, and they may know the titular cyborg identity thieves from Snatcher. But they won’t recognize seeing them together.

MGR was about slicing cyborgs apart with a katana, and Snatcher was a visual novel about uncovering a conspiracy. Jamais Vu has Raiden finding Snatchers among regular troops, then killing them to stop them taking over the world. Once dead, the Snatchers burn up like the Frogs in MGS4. Separately they make sense. Mixed together, they’re confusing.

More: Weirdest Pieces of Cut Content in the Metal Gear Series