Chozo Block



A Chozo Block is an ancient technology present in Metroid: Zero Mission. These depict the three Unknown Items and initially appear to be rock-solid, blocking off Samus from continuing on in her Zero Mission. After collecting the item, however, these blocks begin to flash and can be destroyed by shooting or bombing them. These blocks depict the Item they are guarding, either the Plasma Beam, Space Jump or Gravity Suit. When shot, the blocks flash in a cross shape and disappear. The Plasma Beam and Gravity Suit Blocks also block a Missile Tank and Energy Tank, respectively. These Blocks are also featured in rooms close to the chamber in which the item is located.

Metroid: Zero Mission: The Official Nintendo Player's Guide
"After you collect an unknown item, certain carved Chozo Blocks will flash, signaling that you can destroy them with a beam or bomb blast."