Anchor

An Anchor is an item that first appears in Super Mario Bros. 3.

Super Mario Bros. 3
Anchors in Super Mario Bros. 3 are rare items that can only be received at a special White Mushroom House after collecting a certain number of coins in a certain level in the even-numbered worlds. An Anchor will prevent an Airship from moving if Mario fails to clear it, thereby eliminating the need to trek long distances to try again to complete the level. It also appears in cutscenes before Airship levels, where Mario climbs the chain while the Anchor is being hoisted up.

New Super Mario Bros. Wii
After a long absence, the anchor reappears in New Super Mario Bros. Wii. The first Airship level has an anchor near it before the player actually goes to the level. Anchors do not serve the same purpose as they did in Super Mario Bros. 3, however. When the first two Airship levels are cleared, anchors replace the Airships on the map indicating that the levels have been cleared. Players can still visit the Airship levels, though.

Nintendo Adventure Books
An anchor can be acquired in Double Trouble of the Nintendo Adventure Books series in either Mario Brothers Plumbing or a portion of the Doom Ship, and it can be used by Mario to reach the poop deck of the Doom Ship, where Roy Koopa is holding Luigi captive. An anchor can also be found in the subsequent book, Leaping Lizards, but it is a dud item; its only purpose is to drag Luigi down if he falls into a body of water, causing a Game Over.

Wario Land II
There is also an anchor in Wario Land II that can be found in the SS Tea Cup world. It only appears in the fourth level of Chapter 2 called Drop the anchor!!. Here, Wario has to use his attack to move it and drop it into the water. After it is dropped, the level is completed.

Mario Kart 7
Swinging anchors with Wario's emblem appear in the Wario Shipyard course as obstacles in the underwater section and the gliding section, where they block the player's path. They can be knocked back by touching them while under the effects of a Super Star or a Bullet Bill.

Mario Kart Tour
Swinging anchors return as obstacles in the Mario Kart Tour rendition of 3DS Wario Shipyard and some of its variants. Drivers can push an anchor back (and receive bonus points in the process) by hitting it with a Bowser's Shell, Super Horn, Giga Bob-omb, or a Super Bell, or by touching it while under the effects of a Frenzy, Super Star, Mega Mushroom, or Bullet Bill.

Paper Mario: Color Splash
An anchor appears in Paper Mario: Color Splash as Mario's means of entering the Airship carrying the drained red paint from Crimson Tower, as Johnson neglected to lift up the anchor and thus forced the Airship to stall.

Mario Tennis Aces
In Mario Tennis Aces, Boom Boom uses an anchor to lower himself onto the court in his entrance animation.

The Super Mario Bros. Movie
While Anchors themselves don't appear in the movie, Bowser's Castle uses the Ball and chains as such.

Super Mario Bros. 3

 * Wii Virtual Console manual: Use this item to stop airships from moving.
 * Nintendo 3DS Virtual Console manual: Prevents the Koopa airship from moving to a new location.