Psycho Mantis

Psycho Mantis was a psychic member of FOXHOUND, who assisted in the armed takeover of Shadow Moses Island in 2005. He wore a gas mask to help prevent people's thoughts from "forcing their way into his mind."

Unconfirmed history
Immediately prior to his death, Psycho Mantis foresaw that Snake, as an old man, would place a gun in his mouth.

Behind the scenes
The battle with Psycho Mantis (サイコ・マンティス) in Metal Gear Solid is widely known for him "displaying" his mental powers. This includes making the controller move by activating the rumble feature, making players think the TV channel has changed by turning the screen to black, with the green caption "HIDEO" displayed in the top-right corner of the screen. He also "reads" the player's memory card, commenting on the number of saves that have been made in the game so far, and the presence of other saved games, first noting their genre, then mentioning specific examples. In the original, Mantis mentions Azure Dreams, Suikoden, Castlevania: Symphony of the Night, and Vandal Hearts (plus Policenauts and Snatcher in the Japanese version), while in the remake, he references Super Smash Bros. Melee, Super Mario Sunshine, The Legend of Zelda: The Wind Waker and Eternal Darkness: Sanity's Requiem.

After the boss battle with Psycho Mantis, he will state that he is unsure whether Snake's and Meryl's futures lie together, alluding to the game's two alternate endings; one in which Meryl survives, and the other in which she dies. Additionally, the script for the original Japanese release had Mantis mention that his helping Snake on his deathbed felt "nostalgic," though this was changed to "it feels pretty nice" in the English version (nevetheless, the original dialogue is maintained in the 2003 English language remake The Twin Snakes). According to Hideo Kojima, Mantis's nostalgia was due to him sensing his own mother's emotions during childbirth, where she had used the last of her dying strength to help her son survive; similar to Mantis's own actions towards Snake upon his death.

According to Hideo Kojima's Grand Game Plan for Metal Gear Solid 2, there was originally supposed to be a mask based on Psycho Mantis's likeness (called the Mantis mask), that allowed Raiden to read the thoughts of other characters. One example would be using the mask to discern a SEAL's identity as Solid Snake. This item ultimately never made it into the final version.

The manner in which Solid Snake defeated Psycho Mantis in the Metal Gear Solid novelization was portrayed differently to the game, with Snake tricking Mantis into levitating all the contents of the Commander's Room and making himself vulnerable to attack (Mantis used his psychic abilities to prevent Snake from even touching his holstered gun). Mantis was also successful in placing Snake under his mental control for a brief period of time, causing him to hallucinate the appearance of Master Miller. The illusion involved both Miller and Snake visiting a theme park from Snake's childhood, where he attempted to save Meryl from the funhouse, later encountering her reflection in the funhouse's mirrors, along with that of Otacon and Big Boss himself.

The fight against Screaming Mantis in Metal Gear Solid 4 is designed to play off the player's memory of fighting Psycho Mantis in Metal Gear Solid, right down to the music being a recreation of "Mantis Hymn" from the original Metal Gear Solid. After Screaming Mantis screams "Blackout!" the screen turns to black and displays a green caption saying "HIDEO2." If the player switches the PS3 controller over to Controller Port 2, Snake will call Otacon saying that he can't move, with Otacon telling him that the trick won't work this time, much to Snake's chagrin. Roy Campbell also suggests that Snake try either swapping controller ports or destroying the mask on the bust of Mantis's face, but Rosemary and Snake rebuke him, stating that neither of those strategies is applicable in the situation. After the battle, when Mantis himself appears, he attempts to read the memory card once more, but fails due to the PS3's hard drive-based memory system. He also tries to repeat his controller-moving trick, but is unsuccessful due to the lack of rumble feature in the SIXAXIS controller. Enraged, he disappears after the Sorrow sent his ghost back to the grave. However, if the scene is played with a DualShock 3, Mantis will perform the trick successfully and gleefully declare that vibration is back before disappearing.

Psycho Mantis is also mentioned in Super Smash Bros. Brawl. Roy Campbell can feed Snake data on Ness if he uses his Codec taunt. During the talk, Snake will recall his encounters with Psycho Mantis, to the point of even asking if Ness can also read minds. Campbell assures him that Ness is "a good kid" and would not use telepathic powers to scan Snake's mind against his will, whether he had such powers or not.

Psycho Mantis was previously chosen as the #3 best boss fight ever by GameSpot. He also ranked eighth in IGN's recent "Top 100 Videogame Villains" poll, beating out fellow FOXHOUND members Sniper Wolf, Liquid Snake, and Revolver Ocelot; even beating Big Boss.