Shy Guy Tower

Shy Guy Towers (known as Shy Stacks in Paper Mario) are Shy Guys arranged in a tower formation, described in their Paper Mario tattle as having "an incredible sense of balance."

Paper Mario
Shy Stacks debut in Paper Mario, where they form the third part of the Shy Guy Army. They consist of four Shy Guys standing on top of each other. The Spin Smash Badge or Kooper can be used to knock them off. They use slingshots to attack, like regular Shy Guys in Super Mario RPG: The Legend of the Seven Stars.

Yoshi's Island DS
They also appear in Yoshi's Island DS, along with a Pirate Guy variant. If a Yoshi licks one of the Shy Guys in the stack, they will fall down and become regular Shy Guys.

Yoshi's Woolly World / Poochy & Yoshi's Woolly World
Shy Guy Towers return under their new name in Yoshi's Woolly World and Poochy & Yoshi's Woolly World. Unlike in Yoshi's Island DS, the tower cannot be disbanded by removing a single Shy Guy from the formation; however, this is not the case when Yoshi steers through them as Moto Yoshi. When one of them is eaten or attacked with a Yarn Ball, any other Shy Guys that were staying on top of it drop a level lower. They can also be stomped on one by one, or Ground Pounded from the top to instantly defeat all of them. Often, the Shy Guy at the top of the tower holds a Bead or a Bomb.

Yoshi's Crafted World
Shy Guy Towers are set to reappear in Yoshi's Crafted World. Their role as an enemy is currently unknown.

Mario Sports Superstars
Shy Guy Towers later reappear in Mario Sports Superstars in the "Road to Superstar" mode as enemies, though only two Shy Guys stand on top of each other. They can be defeated by the sports balls that the amiibo cards yield.

Mario Tennis Aces
Shy Guy Towers reappear in the "Shy Guy Train Tussle" co-op challenge of Mario Tennis Aces. They appear in stacks of their respective colors just like in Yoshi's Island DS, and can be hit for coins.