Egg Block

Egg Blocks, also called Egg Boxes, are blocks in the Yoshi franchise which dispense Yoshi's Eggs for Yoshis to throw.

Yoshi franchise
Egg Blocks are commonly green, but in Yoshi's Story, they are the color of the current Yoshi. When Yoshi hits this block from the bottom, a Yoshi's egg will be dispensed, provided he has space to carry more eggs. If Yoshi is already holding six eggs, no more eggs will be dispensed. Aside from green Egg Blocks, in the Yoshi's Island there are also Yellow and Red Egg Blocks which, when hit, turn into a single Yellow Egg or a Red Egg respectively.

In Yoshi's New Island, two new Egg Block varieties are introduced. One of them releases Mega Eggdozers, while the other one releases Metal Eggdozers. Both of them are four times bigger than a normal Egg Block (looking like green Expansion Blocks). The earlier variety is white, while the latter is black.

In Yoshi's Woolly World and its 3DS port, Egg Blocks are replaced by similarly designed objects known as Yarn Baskets, matching the game's aesthetics. They serve the same purpose as before, but instead of regular Yoshi eggs, they release yarn balls, the game's equivalent of Yoshi eggs. Occasionally, they will release bigger yarn balls for the Yoshis to use. Yarn Baskets can be hit from the bottom to release one yarn ball at a time, or hit with a yarn ball from any side to release multiple at once.

In most games, hitting an Egg Block from a certain side will push eggs out in the opposite direction. However, in Yoshi's Crafted World, the direction in which eggs are dispensed depends on the direction that Yoshi is facing.

Sonic Lost World
In the Wii U version of Sonic Lost World, Egg Blocks appear in the DLC stage "Yoshi's Island Zone", where Sonic must save Yoshis inside Yoshi eggs and bring them to the goal at the end of the level. Only three Yoshi eggs will come out regardless of how many eggs are currently following Sonic.

Yoshi's Woolly World / Poochy & Yoshi's Woolly World

 * Instruction Manual description: "Bump it from below or shoot it with a yarn ball to make yarn balls come flying out."
 * "You can hold up to six yarn balls."

Square Egg

 * In Super Mario 64 DS, if Yoshi swallows a wooden box, the Egg he creates will be in the shape of a cube, just like Egg Blocks.
 * In Super Mario Sunshine, in a secret level in Pinna Park, there are four colored Yoshi Egg Blocks, colored magenta, green, blue, and black.

Trivia

 * In Super Princess Peach, the design of the breakable blocks in Hoo's Wood greatly resemble that of Egg Blocks.