Shy Guys are undetermined enemies of the Mushroom Kingdom and have served as progressive antagonists in the Mushroom World. Shy Guys don't seem to care about what they're doing as long as it entertains them.
The Shy Guy character first appeared in the Japanese-only game Doki Doki Panic, which was later converted into the American release of Super Mario Bros. 2 and in the later released game title Super Mario Bros USA.
Shy Guys are the main foot soldier-style enemy throughout the Yoshi series, appearing on foot, stilts, flying with the assistance of balloons, jet packs and rockets, or piloting submarines. They are also known to partake in limbo and enjoy watering plants or doing backflips.
While Shy Guys appear in Mario games as enemies, Shy Guys are playable in various Mario spin-off sports-themed games, such as Mario Tennis, Mario Kart DS, Mario Strikers Charged, and Mario Superstar Baseball.
Shy Guys show up as guides in the Mario Party series and as judges in Mario & Sonic at the Olympic Games.
In Mario Power Tennis, a Shy Guy's mask falls off during the trophy ceremony if the player wins a tournament with Luigi. Although its face is not visible to the player, Luigi is terrified by it.
These are various Shy Guys who differ physically, rather than those bearing different objects or weapons.
A Shy Guy who has wings on it's back allowing it to fly, and attacks with a trident, appearing in Super Mario Bros. 2 and Advance. Also referred to as Shy Aways in Super Mario RPG: Legend of the Seven Stars.
This is a Shy Guy who is white in colour with a wispy tail and floats just above the ground (similar to Boo) and can operate machinery. Ghosts also appeared in Luigi's Mansion in the form of Shy Guys.
Flying Shy Guy
Not to be confused with the Fly Guy, this is a Shy Guy which has a propellor on it's back rather than it's head. These appear in Yoshi's Story, for the most part simply carrying fruit, however a black variant of the Flying Shy Guy also has the ability to drop anvils. Cameos are also made in Super Smash Bros. Melee and Brawl.
Appearing in Mario Party 3, this Shy Guy wears a casino-style shirt and lets the players play his special minigames when you land on his space for a chance to win coins.
Shy Guy with an umbrella on it's back, enabling it to glide through wind currents, countering the abilities of Baby Peach in Yoshi's Island DS.
Only appearing in Paper Mario, Shy Guy wearing a court jester outfit, who instead of physically attacking, will make opponents dizzy whilst summoning other Shy Guy species.
Again, only ever appearing in Paper Mario, can heal their partners in battle and run into enemies with their flying ambulances.
Mini Shy Guy
The living, miniature Shy Guy toys which appear in the Mario vs. Donkey Kong series. A similar mesh between this and the Fly Guy is also a purchasable item in the original Mario Party, which counted how many times the control stick was rotated, and then flew around the room for an accordant period of time before passing comment.
An undead Shy Guy from Mario vs. Donkey Kong 2: March of the Minis who will break apart when stepped on (similar to Dry Bones), but will reform soon after.
Shy Guy dressed in typical pirate garb, who sails around Yoshi's Island on a ship armed with Bob-omb and Bullet Bill cannons. Appearing in Yoshi's Story and Yoshi's Island DS, they also play a key role in both Mario Kart Wii and Super Circuit, specifically on the Shy Guy Beach course. Cameos are also made in Mario Party 1, 2 and 8, plus Mario Hoops 3-on-3.
A Shy Guy which has caught fire and can typically run twice as fast. First appeared in Super Mario World 2: Yoshi's Island, where they would empower Yoshi with three shots of fire when eaten. Later appeared in Tetris Attack as Gargantua Blargg's assistant, and again in Paper Mario.
Seen throughout the Yoshi series, this is a tribal Shy Guy who wears face paint, a grass skirt and attacks with a spear, also known as Jungle or Chuck Guys. The Fly Guy also uses a similar spear in Mario Hoops 3-on-3.
A Shy Guy wearing camouflage gear seen in Paper Mario. Another similar relative is the Mufti Guy , which have flowers on their heads and hide in gardens.
A Shy Guy with black clothing, a purple mask and purple shoes that only appear in Paper Mario. Although no difference in look other than the palette swap, they have a large difference in health and attack power compared to the other Shy Guys and give a large amount of Star Points when defeated. They are also one of the strongest enemies Mario can fight in Paper Mario. In total there are 4 Anti Guys in the entire game, one in Shy Guy's Toy Box who is guarding a chest with a Power Plus badge inside and three in Bowser's Castle awaiting the player to get three questions wrong (a part in which you must answer 5 questions to pass the gate blocking your way).
Another now infrequent cousin of the Shy Guy is the Snifit (also known as the Gunner Guy in a military setting), which wears a black mask and has a cannon for a mouth, firing various projectiles such as Bullet Bills or nightmares.
Shy Guys make their cameo appearance in the Zelda series by appearing as enemies in The Legend of Zelda: Link's Awakening, known as Mask-Mimics.