Chomp Rock
Chomp Rocks are round stones that look like Chain Chomps in Super Mario World 2: Yoshi's Island and its sequel. They appear in many levels and are used for moving through soft rock, and reaching high areas. In some levels they are an obstacle, such as when they need to be rolled off a thin pillar to reach a key. Some Sluggers hit these back and forth, resulting in a dangerous area to cross over. In the Yoshi's Island games, Yoshi can push Chomp Rocks forward or moonwalk on top of them to roll them where he wants them to go. He can easily use Chomp Rocks to crush most enemies easily, even otherwise-invulnerable foes, such as the occasional Tap-Tap.
The difference between the gray and brown Chomp Rocks in the original game is that the gray ones will go back to their starting point if the player leaves the screen, and the brown ones will not. However, neither color goes back in the sequel, except for the one in the Island Museum's Land Enemy section - which happens to be brown.
Chomp Rocks made a cameo appearance in Paper Mario. They were found in the background of Dry Dry Ruins and were easily confused with Stone Chomps (the difference is that Stone Chomps are alive, while Chomp Rocks are inanimate objects). They are also seen outside the Dry Dry Ruins, on decorative pedestals surrounding the outside. Paper Mario's Chomp Rocks had slightly gaping mouths.
Chomp Rocks (only two of them) made yet another appearance in Paper Mario: The Thousand-Year Door. In this incarnation, the rocks were hollow and had open mouths. They sat on top of Warp Pipes, preventing entry. Mario could destroy the rocks by throwing Admiral Bobbery into the gaping maws of the rocks. When Bobbery exploded, the rock was destroyed.
The brown Chomp Rocks also made an appearance in Mario & Luigi: Partners in Time when the Yoshis had to move them on two occasions to open up new path's in Yoob's Belly. Five Yoshis could also use a Chomp Rock to lower Sunnycide's defense after the Mario Brothers freed them from Yoob eggs.
They look like small statues of Chomp Heads and can come in three colors: turquoise-grayish, gray, and brown.
In the Club Nintendo comic "Mario's Picross", Mario got arrested inside a pyramid. He came across a treasure chamber with a chest inside. When trying to pick up the treasure chest, a Chomp Rock was released through a trap door and started rolling towards Mario. He could only escape from the rock by jumping into a lorry and moving away.
